During the Great War, Zeratul was a tutor to Tassadar in the ways of the Dark Templar. Called to the Imperial Sanctum by Tassadar's phantom, Zeratul arrives to aid his pupil however he can.
While Zeratul suffers from his small health pool and melee range, his ability to secure ganks and pick off squishy heroes with his ultimate allows him to be very versatile in teamfights due to the Chronosphere.
Gameplay
Cool video depicting the evasiveness of Zeratul
Skills
Clairvoyance
Passive: Zeratul remains cloaked so long as he is within 10 units of an enemy hero. Dispels on attack or spellcast. Recloaks after 3.25 seconds.
Phase Strike
RANGE: 7
COST: 55 / 60 / 65 / 70 mana
COOLDOWN: 30 / 24 / 18 / 12
Active: Zeratul leaps behind target enemy, dealing Spell Damage and (+100 Weapon Damage) Physical Damage. Whenever Zeratul kills a unit, Phase Strike's cooldown is reset.
Spell Damage: 30 / 60 / 90 / 120
Unfolding Fate
Passive: When attacking enemies from behind, Zeratul deals bonus Spell Damage.
Spell Damage: 30 / 40 / 50 / 60 (% AGI)
Planar Void
COST: 80 / 90 / 100 / 110 mana
Active: Zeratul twists space, generating a circular wall that lasts 0.5 seconds and will transport anyone who touches the border to the opposite side of the circle. Enemies transported this way are stunned for the duration of the wall +1 seconds.
Cooldown: 20 / 18 / 16 / 14
Chronosphere
RANGE: 7
COST: 150 / 250 / 350 mana
COOLDOWN: 120 / 100 / 80
Active: Zeratul bends time itself to his favor, silencing all units and slowing down time in an area by 80%. Zeratul's long experience as a time traveler renders him immune to the effect.
With two skills that can be as harmful as hurtful to your team if used improperly, Zeratul is a high burst autoattack carry/initiator with large potential to succeed or fail spectacularly. Mastering use of his E is absolutely vital, as it proper positioning with his R to avoid teammates. He is also rather squishy, and is best suited to counter engage unless a large opportunity presents itself. Max Q first for aggressive play, or W for ease of denying. Run 2/1/3 talents, taking attack damage, attackspeed, health, cooldown reduction, energy regen, and movespeed.