the point of this thread is to inform the evoker community since the skill descriptions in game are so ambiguous. It's definately a work in progress, i'd like to have them all here eventually. If you think the wording is confusing or you see an error please correct me.

(but i got bored and lazy so it's not done, but i'll put more later also with some pictures of the skills in use)

look here for level requirements and prerequisite skill info


FIRESTORM
Descriptions: Conically shaped short stream AOE; last as long as you hold down the key/button
There is a chance to ignite that is attached to firestorm that increases as you add points to it.
Damage type:fire
Rate of use: continuous
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: high power cost, x/sec
Range: low, 8 meters
Benefit from skill addition: ignite chance increases (starts at 0 ends at 675%)
Other information:
-Increased rate of use mods adversely effect firestorm causing an extreme power drain discussion on this and another one

FLAMESHARDS
Descriptions: You click the key/button and your character throws shards out (the number varies on your skill level)
they spray out in a uniformly spaced fan shape and randomly embed in objects or enemies where they hit; the radius of damage is one meter but it is not expressed when the shards are embedded in a mob (see other information). once embedded, the shard will explode after one second.
Damage type:fire (can proc ignite with ignite attack strength or all element attack strength)
Rate of use: 1 second recast time
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: low-moderate
Range: midrange, 20 meters
Benefit from skill addition: number of shards increases (starts at 5 ends at 14)
Other information:
-multiple shards embedded in an enemy in one cast do only the damage of one shard (it is unknown if this is a bug or intended) thread about that
-shards embedded in the environment (walls/floor) or other enemies can do full damage to other enemies in range

HELLFIRE
Descriptions: You click and a beam comes out of your focus pointing towards the ground signifying the start of the cast; you are free to move around during this time but must not cast any additional skills. After 2 seconds a pentagram/circle shape materializes on the spot where the tip of your beam was last located, followed quickly by an eruption of fire from the ground that blankets a ~15m area around where the circle was; any enemies in this vicinity take direct fire damage from the eruption and then additional fire damage over time for 4 seconds.
Damage type:fire (can proc ignite with ignite attack strength or all element attack strength)
Rate of use:No recast/cooldown
Cast Time: 2 seconds
Delay before another skill can be used: unknown
Power cost: high to mid (the more points you add to hellfire the lower the power cost)
Range: long range: 28 meters
Benefit from skill addition: power cost is lowered (at level 10 it is roughly half of the level 1 power cost)
Other information:
-you can change the position of where hellfire will emerge for as long as the beam is out; once the circle symbol is observed that is the spot where hellfire will be cast
-you can spam this skill (use it repeatedly) though the fields will not overlap with themselves or other aoe fields


SPECTRAL BOLT
Descriptions: You throw a single ball shaped projectile that (if it goes far enough) splits into several (up to 10?) bolts; the split occurs at around 15 meters. The balls do damage and have a chance to phase enemies; the chance goes up with spectral bolt's skill level.
Damage type: spectral
Rate of use: 1 second recast time
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: low-moderate
Range: long range, 28 meters
Benefit from skill addition: chance to phase is increased (100% at level 1, 1900% at level 10)
Other information:
-if spectral bolt hits before 15m then only 1 ball hit; there will be no split
-movement of the balls after the split is unpredictable
-with correct positioning you can get multiple balls to hit one target, each doing full damage

SPECTRAL LASH
Descriptions: A line appears that is attached to your focus weapon(s); it latches on to your target and does damage for as long as you hold down the key/button; the connection is not lost if you move or if the target moves. (but will be lost if you lose line of site)
Damage type: spectral (can proc phase with phase attack strength or all element attack strength)
Rate of use: continuous
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: low, x/sec
Range: midrange to very long range, 18m-45m(depends on skill level)
Benefit from skill addition: range increases from 18m at level 1 to 45m at level 10
Other information:
-it's "latching on" feature allows for a lot more movement and maneuverability


SPECTRAL LASH MASTERY
Descriptions: A passive skill that works with (and only with) spectral lash; it causes enemies killed by lash to explode; the explosion has lowish damage but the explosion also has a chance to phase enemies.
Damage type: spectral
Rate of use: n/a (see other information)
Cast Time: n/a
Delay before another skill can be used: none
Power cost: n/a
Range: n/a (range of explosion unknown)
Benefit from skill addition: increased chance for the explosions caused by mastery to phase (100% at level 1, 1900% at level 10)
Other information:
-lash mastery explosion/debuff can only occur every 2 seconds
-most people find that both the damage and chance to phase are too low thread about that

LIGHTNING FIELD
Descriptions: You throw a ball shaped projectile that can do a small amount of damage if it hits an enemy, but doesn't need a target (it can be thrown on the floor); either way the ball breaks upon impact and does an AOE around the floor of the landing point. The AOE area is determined by skill level and the area stays "electrified" for ~5 seconds.
Damage type: lightning (can proc shock with shock attack strength or all element attack strength)
Rate of use: no recast/cooldown
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: moderate
Range: long range, 30m
Benefit from skill addition: increased AOE area after the ball hits (14ish% to 126ish% at level 10)
Other information:
-lightning field and swarm AOEs cannot overlap (and 2 or more lightning fields cannot overlap on themselves)

TEMPEST
Descriptions: You cast (rising up with a cool animation and a lightning bolt coming from your hand to the sky) and an AOE cloud emerges overhead that does damage through lightning strikes; the lightning targets enemies under the cloud and the number of strikes is determined by tempest's skill level. The cloud lasts for over 20 seconds. (23?)
Damage type: lightning (can proc shock with shock attack strength or all element attack strength)
Rate of use: 20 seconds
Cast Time: 5 seconds
Delay before another skill can be used: unknown
Power cost: high
Range: low (30m straight UP!)
Benefit from skill addition: increased lightning strikes (20% at level 1, 180% at level 10)
Other information:
-it roots you for 3 seconds while you cast it
-luring or fearing enemies under the cloud is one way to use it
-discussion on Tempest's usefulness
-i've heard the clouds can overlap and stack but have not confirmed it myself
-one something steps under the Tempest cloud, it can remain a target even if it leaves the area under the cloud; lightning strikes will continue to hit this target if another is not readily available for up to 30m; past 30m lightning strike animation will persist but damage is not done

ARC LEGION
Descriptions: Another leash skill that works like a shorter range multi target lash; lines come out
from your focus, then seek out and attach themselves to enemies. If only one target is present only one line will attach;
if multiple enemies are around the stream and the damage of the stream is split.
Damage type: lightning (can proc shock with shock attack strength or all element attack strength)
Rate of use: continuous
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: low-moderate, x/sec
Range: low to midrange, range depends on skill: level 11-20 meters
Benefit from skill addition: increased range 11m at level 1, 20m at level 10
Other information:
-it has a feeling of building up strength when compared to lash (that is full strength and fully attached at start)
-damage to one target is substantially more than damage to several


VENOMOUS SPIRIT
Descriptions: Little ghosty guy shaped projectile comes out from your focus weapon and flies in a straight line on whatever plane you threw him on until he encounters an enemy; the spirit projectile acts like a homing device toward enemies, auto-targetting them. When he hits an enemy there is upfront damage that is inflicted and also the chance for poison damage and a chance to fear.
Damage type: toxic (can proc poison with poison attack strength or all element attack strength)
Rate of use: 1 second
Cast Time: negligable >.5 sec
Delay before another skill can be used: none
Power cost: low-moderate
Range: long range, 35m
Benefit from skill addition: increased chance of fear (20 at level 2, 180 at level 10)
Other information:
-some people find the speed of the projectile to be too slow, others use it's mechanics to hit a single target long range with 3 or more venomous spirits in conjunction with another skill used as the spirits hit to do high dps.
-fear does not work in pvp
-"The Spirit can also be used as a mob seeking missile. If you shoot the Spirit straight in front of you at an intersection or down a hallway and the Spirt swerves either left or right there is a mob there. The Spirit will auto-target mobs that are close by if you lob it in the general direction. Very handy to have if you want a bit of intel before getting ganked in a dark alley." -Ratero


VENOM ARMOR
Descriptions: You cast and your hands glow for a sec then you're surrounded by a circle of bugs that persists with you as you move. Your armor is increased by a set amount determined by two things: your character's level and Venom Armor's skill level. The bugs that surround you will attack anything that gets in close proximity doing damage over time for about 8 seconds regardless of the position of the infested enemy; (an enemy can get within 4m of you the bugs will attack it and continue to do so whether he remains at 4m or if he runs away to 30m.)
Damage type: toxic (can proc disease with disease attack strength or all element attack strength)
Rate of use: 60 seconds
Cast Time: instantly on
Delay before another skill can be used: 3 seconds
Power cost: moderate-high
Range: the bugs will attack anything that is within 4m or so of you; however they can also follow along the lines of enemy skills or weapons and so you can deliver Venon Armor's damage in a longer range in this manner.
Benefit from skill addition: increased armor value (160 at level 1, 250 at level 10) and increased duration (20 seconds at level 1, 65 seconds at level 10)
Other information:
-an enemy inflicted with Venom Armor's bugs will take increased damage with each attack he makes; the bugs sort of counterattack with every hit or shot or skill used by an enemy
-armor value is approximately 400 at level 50, granting 60% damage mitigation
-an infection phenomenon is observable: bugs can spread from one enemy to a second upon the death of the first
-bugs can follow enemy streams to attack them at further range
-venom armor can be casted as you run without stopping
-concentrate damage and arcane shield can be used during the 3s delay
-using conc dmg during the cast of venom armor appears to have no effect, however the damage caused by the bugs on an attacking foe appear to gain additional damage when conc dmg is used

SWARM
Descriptions: You throw a small circular projectile and where it lands there's this puddle effect animation (as if a stone dropped in water) and a field of bugs immediately rises from the ground; the field appears to be about 15m in diameter and lasts for about 7 seconds. Anything that crosses into the field will be attacked by bugs and take damage over time.
Damage type: toxic (can proc disease with disease attack strength or all element attack strength)
Rate of use: depends on skill level; lowered recast time at higher skill level
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: high
Range: long range, 30m
Benefit from skill addition: increased rate of use (20s rate of use at level 1, 7.1s rate of use at level 10)
Other information:
-lightning field and swarm fields cannot overlap (and swarm fields cannot overlap themselves either)
-enemies that leave the field will continue to take damage for 1 second
-when the cloudiness on the floor dissepates thats when the aoe has ended and enemies stop taking damage; there is an additional 1-1.5 seconds of bugs animation where enemies do not take damage in the area


DEMONSPINE
Descriptions:You fire a projectile (shaped like a line about 1m long) at your target; both the delivery and speed of the projectile have the appearance and feel of going faster than other projectile skills. The projectile pierces through targets meaning that it doesn't stop when you hit your target, the projectile continues to move through any others behind the first within range. When it hits an object or enemy there is the appearance of a small impact explosion but it does not do damage to any adjacent enemies. Demonspine also has a chance to stun that increases with its level.
Damage type: physical
Rate of use: 1 second
Cast Time: negligable >.25sec
Delay before another skill can be used: none
Power cost: low
Range: midrange, 20m
Benefit from skill addition: increased chance to stun (1100% at level 1, 3800% at level 10)
Other information:
-you fire demonspine straight out from your focus weapon, you don't lob it (shift weight and lean back and arc it as you throw) how you do with other skills so this in part is why it seems faster

BONESHARDS
Descriptions: It is instantly casted as you push the key/button, a bunch of popcorn looking bone pieces fly outwards in a dome shape around your character. They damage enemies in range and have a chance to stun; the stun chance increases with its skill level.
Damage type: physical
Rate of use: 8 second recast
Cast Time: instantly casted
Delay before another skill can be used: 2 seconds
Power cost: low
Range: 10m in all directions
Benefit from skill addition: increased chance to stun (1200% at level 1, 5700% at level 10)
Other information:
-concentrate damage and arcane shield can be used during the 2s delay
-the bone pieces flying out can miss mobs that fall between them
-every other cast of boneshards will do no damage if you do not cast anything between the two boneshard casts

SKULLSPLITTER picture of use in open area and at skill level 1 (only a few fragments)
Descriptions: You throw a softball looking projectile that bounces once if it hits a surface at or under 10m then it impacts on it's next surface encounter; however, a fragment of the original, observable only by it's impact, continues onwards exploding either further forward or adjacent depending on the area; then another explosion after the second, and this continues for however many fragments your skill level grants. The impacts and explosions following the first occur in rapid succession.
The fragment explosions appear to continue on leaping forward like skipping stones if the area of the projectile's path is open; if there is no space to continue forward the fragments impact adjacent to the original provided that the area of impact is at 10m or greater; under 10m there will be only one impact and no fragments. If you throw it downwards at the floor within 10m it will bounce onwards or up to a wall if it cant go forward; if you throw it downwards at the floor beyond 10m it will impact. Enemies encountered along the first projectile's bouncing path are damaged. Upon impacts there are explosions appearing to be about 5m in diameter and damaging enemies within this range.
Alternate Description because mine is dumb:"You throw a softball-type projectile which goes a maximum of 20m, with some exceptions. The skull will go 10m bouncing one time, and one time only then it travels as far as it will go (max of 20m) until exploding. If the skull flies 10m in the air and then hits the ground, it explodes on impact. Once the skull explodes X amount of shards go flying in random directions, exploding on impact, creating a 2m radius explosion, which damages all enemies in its explosion. The skull will not explode into its shards if it hits an enemy directly"-virus
(maybe between the both of them it's understandable)
Damage type: physical (can proc stun with physical attack strength or all element attack strength)
Rate of use: 5 second recast
Cast Time: negligable >.5sec
Delay before another skill can be used: none
Power cost: moderate-high
Range: midrange, 20m
Benefit from skill addition: increased number of split fragments (4 at level 1, 13 at level 10)
Other information:
-the range of 20m may not always apply (i've gotten fragmented explosions to go much further)
-If a skullsplitter's original projectile "whizzes" by an enemy, the enemy will take damage.
-movement of the fragmented explosions is based on both the angle/direction of the inital projectile and on the terrain, but it also seems somewhat random and unpredictable.

ARCANE SHIELD
Descriptions:You click the button/key and arcane shield is immediately active; a hellgate symbol (circular slowly spinning and flickering) appears below your feet and your shields are healed to full and then an additional shield value (determined by the skill level) is applied on top. You are rooted for one second before you can move; once you move forwards or backwards or strafing, the additional value that was added to your base shield value is lost. (spinning the camera around and spinning yourself in one spot does not cause the spell to break. Unlike other skills the recast does not start counting down until after you have moved and broken the original cast; until then and while active the skill blinks red indicating that it is in use and cannot be reused.
Damage type: n/a
Rate of use: 13 second recast time
Cast Time: instantly on
Delay before another skill can be used: none
Power cost: low
Range: n/a
Benefit from skill addition: increased shield value
Other information:
-you are rooted for one second after casting arcane shield
-shield regeneration is determined by max shield value (the higher your shields the faster your regen)
-damage done to shields is calculated without regard to armor values (i think)
-shield overload increases the percentage damage done to shields
-shield penetration causes a percentage of damage to ignore shields
-there is an issue that shields seem a lot less useful in higher levels here's a thread on that
-because of the previous issue most people only put 1 point to arcane shield and use it as a shield heal skill only rather than relying on it to augment their shields to a level where it would mitigate most damage.

DRAIN POWER
Descriptions: A continuous stream skill: you click the key or push the button and a enemy seeking blue ray comes out from your focus. Once it connects it does no damage but your power regeneration (determined by skill level) is increased by a percentage for as long as you hold down the key/button, maintain line of sight, and stay in proper range; if there are two or more enemies in range and close enough together (about 5m apart) the stream will split to multiple enemies and you will regenerate the increased percentage of power for every enemy in the stream.
(more enemies drained = more power regenerated)
Damage type: n/a
Rate of use: continuous
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: n/a
Range: midrange, 21m
Benefit from skill addition: increased power regeneration (20% at level 2, 120% at level 10)
Other information:
-this is the only skill besides dual focus that does not require power
-some people say that it does not scale well at higher character levels
-power drain does not drain power from enemy players

DRAIN LIFE
Descriptions: A continuous stream skill: you click the key or push the button and an enemy seeking red ray comes out from your focus. Once it connects it does a slow amount of damage over time and you gain a set amount of life over time (determined by both skill level and character level) for as long as you hold down the key/button, have power, maintain line of sight, and stay in proper range; if there are two or more enemies in range and close enough together (about 5m apart) the stream will split to multiple enemies and does not appear to lose damage from this split; however, you will gain life from each mob that is in the stream and you will lose 13 power per second for every enemy in the stream.
(more enemies drained = more life gained = more power lost)
Damage type: n/a
Rate of use: continuous
Cast Time: negligable <.5sec
Delay before another skill can be used: none
Power cost: low to high depending on the number of enemies being drained
Range: midrange, 21m
Benefit from skill addition: increased health gained
Other information:
-the damage is low about 1/3 or 1/4 the damage done by spectral lash
-some people say that it does not scale well at higher character levels, while other people are "addicted" to its use

ELEMENTAL DRAIN
Descriptions: Partially a continuous stream skill: you click the key or push the button and a enemy seeking red and blue ray comes out from your focus; you do not need to hold down the button/key though; the stream will maintain itself for 3 seconds provided that you do not lose line of sight or move out of range. After 3 seconds a sparkly kind of bubble effect appears over you and your target; the effect increases your resists by a set number and reduces your enemy's resists by a set number for 8 seconds; both your resist amount increased and the amount that is decreased on your enemy is determined by the skill level. (see other information) Unlike most other skills recast time does not start until the stream stops and the effect starts.
Damage type: n/a
Rate of use: 5 seconds
Cast Time: negligable <.5sec but stream must remain active for 3seconds before resist effects apply
Delay before another skill can be used: none
Power cost: moderate to high
Range: midrange, 21m
Benefit from skill addition: increases your resists gained, increases enemy resists lost (see other information)
Other information:
-the skill is bugged in that it says you gain a percentage resists and enemies lose a percentage resists but the actual resists that you gain are not percentile (when it says 60% it really means you gain 60 to all resists) - this is the same for your enemys resists (that it is only decreased by a set number and not a percent)
-you cannot maintain this skill on more than one enemy; if you can get the effect to go on two enemies at once it cancels on the first
-i have an an experience in pvp where my enemy GAINED the same amount of resists that i gained, but i have since tested it and this incident has not reoccured; in subsequent tests my enemy in pvp lost resists though they were less than they should have been (he lost 15 to all resists instead of the 25 suggested at level 1)
-the amount of resists gained or lost seems nearly negligable when considering the amount of resists at end game
-if the stream (that must remain up for 3 seconds before the effect becomes active) is broken before the 3 seconds, the skill's recast timer will begin and there will be no resist effects applied
-if a monster dies before the effect has worn off you still keep your side of the effect (the resists gained)
-the skill doesn't draw agro
-increased buff duration mods will increase the 8 seconds that elemental drain's effect is applied to your resists
-there is a bug i've noticed on many occasions where the skill will be red (indicating that it cannot be used) until an enemy is targetted regardless of the distance away (it can be substantially out of range) and then elemental drain will stop being "redded out" indicating that it can be used

BROM'S CURSE
Descriptions: A curse skill: you click the key or push the button and your character will stop in place and lift his/her arms into the air and a set amount of enemies (determined by skill level) within a 14m radius will be cursed; a red vampire-fang-looking symbol will appear above a cursed enemy's head. Any damage done by you to the cursed enemy by skill or weapon (or drain power/drain life) or a thorns item will result in a percent of your life returned(% determined by skill level); this is the same for anyone that attacks an enemy cursed with Brom's curse, they will also have a percent of their life healed for each tic of damage delt as well. The length of time that the curse will remain on the target is determined by skill level.
Damage type: n/a
Rate of use: 2 second recast time
Cast Time: 1.5 sec
Delay before another skill can be used: none
Power cost: moderate
Range: low, 13m
Benefit from skill addition: increased % of your life returned (8% at lvl 1, 14% at lvl 7), increased duration (10seconds at lvl 1, 16 seconds at lvl 7), increased amount of enemies that can be effected by curse (6 enemies at lvl 1, 18 enemies at lvl 7)
Other information:
-the range listed in game is mistsaken, the range is only 14m not 15m
-the range can be increased with increased % range modifications
-curse length can be increased with increased % duration modifications
-the amount of life returned is a percent determined by your total life after item attributes are applied
-life is returned upon each tic of dmg done or each interval of the continuous use skills (for instance just click the continuous use skill instead of holding it down and that time period is the interval for which % life will be returned, and the following interval will return another %) - damage over time skills will return life in a similar fashion: % life will be returned for damage done during the intervals of the time the dot is active for however many intervals of the dot that the curse remains on the enemy.. the result is that because of the short time intervals of the continuous rate or dot skills.. broms will proc at an incredible rate when used in conjunction with these sorts of skills
-because of the aformentioned mechanics, broms and venom armor is considered by some to be an overpowered combination (bugs attack enemies as they attack and so every time you are attacked you are healed usually for more life than was taken)
-elemental drain does not trigger broms
-thorns items trigger broms
-the curse skill animation requires a stationary position, so if you are running and you cast brom's you will stop and stand still and cast it

SPECTRAL CURSE
Descriptions: A curse skill: you click the key or push the button and your character will stop in place and lift his/her arms into the air and a set amount of enemies (determined by skill level) within a 8m radius will be cursed; a glowy purple light will appear above a cursed enemy's head. A cursed enemy that dies will explode on death damaging enemies within a 2m radius; the explosion also has a high chance to phase.
Rate of use: 2 second recast time
Cast Time: 1.5 sec
Delay before another skill can be used: none
Power cost: moderate-high
Range: low, 8m
Benefit from skill addition: increased duration of curse (10 seconds at lvl 1, 55 seconds at lvl 10), increased number of targets (6 at level 1, 24 at level 10)
Other Information:
-the range listed in game is mistsaken, the range is 8m not 10m
-the range can be increased with increased % range modifications
-curse length can be increased with increased % duration modifications
-the way the damage done by the explosions is determined is unknown
-there appears to be a bug that enemies that were once cursed will continue to explode and phase enemies even after the curse has expired (bug reported)
-the curse skill animation requires a stationary position, so if you are running and you cast spectral curse, you will stop and stand still and cast it
-spectral curse works best if you can get a lot of mobs clustered together; then a chain effect of explosions can be accomplished (also works well on bosses surrounded by smaller enemies)


AFTERLIFE
Descriptions: You click the key or push the button and your character stops and does this bendy sway cast for 3 seconds; if there are corpses within 10m of your character (that were not killed by ignite) then red streams will appear from the corpses to your character and you will gain life from each corpse at 2 seconds into the cast; the life gained from each corpse is determined by character level and total life.
Damage type: n/a
Rate of use: depends on skill level; lowered recast time at higher skill level
Cast Time: 3 seconds, (life gained after 2 seconds, end of cast at 3)
Delay before another skill can be used: none
Power cost: moderate
Range: low, 10m
Benefit from skill addition: increased rate of use (20 seconds at level 1, 4.3 seconds at lvl 10)
Other information:
-the skill will remain unusable (redded out) if your health is full (does not always apply.. sometimes if you've recently taken damage but healed back to full the skill will remain usable)
-life returned from corpses is determined on character level and total life AFTER stamina bonuses and any % health bonuses are applied
-the skill animation requires a stationary position, so if you are running and you cast afterlife you will stop and stand still and cast it
-enemies that died while ignited will not leave a usable corpse for afterlife


[some more skill descriptions -> here]

biggest contributors (in no order) to this info and the q and a:
maker nioden virus possibley brotherlaz marsbar velius yudainao wufly astos adamx ratero
(and the dude that made the skill calculator i forgot his forum name )
thanks to them