Hei: Black Reaper
Hei is the main protagonist of Darker than Black
Abilities
(These are just from observation. Forgive me if I get anything wrong.)
Q - Hei throws his dagger in a straight line, dealing physical damage to up to 3 enemies hit. Can crit and applies on hit effects. Adds some sort of buff for each enemy hit which increases crit chance for a few seconds (not 100% sure)
W - Passive: Gives Hei armor penetration and reveals low health enemies in a radius around Hei, much like Warwick's E
E - Hei enters stealth after a 1 second fade time. The next auto-attack after stealth will deal bonus damage. The stealth can only be broken by auto-attacking or using an ability.
R - After a brief channel, Hei will teleport to a target unit. If the unit is an enemy, then Hei's next auto-attack against that enemy will deal bonus damage.
Passive - Whenever Hei crits with his auto-attacks or his Q, he also slows the enemy hit.