Life stealing
From GuildWiki
Life stealing moves health from one character to another. It is not considered damage and will not trigger or be affected by any skill/equipment effects related to damage.
If your character uses a skill or effect that would steal more Health than a foe actually has, the foe will lose the full amount of Health, but your character will not be healed for more Health than the foe actually had.
For a list of all skills which steal life, see life steal skills quick reference.
These skills involve life stealing in other ways:
Grenth's Balance[1] causes the caster to gain half the difference in health between caster and target and the target to lose an equal amount of health. This is not technically life stealing.
Bloodsong creates a spirit whose attacks steal life.
Vengeful Weapon wielder steals life from attacker on taking damage (one-time effect).
Vengeful Was Khanhei (Elite) steals life from attackers while you are holding the ashes.
Nightmare Weapon causes the next three successful attack do less damage, but steal life.
Weapon of Remedy (Elite) wielder steals life from attacker on taking damage (one-time effect).
↑ Grenth's Balance is an anomalous skill: it will also balance the health of the caster and target if the target has less health than the caster and the caster does not have maximum health. This is believed to be a bug.
Also see vampiric for the weapon upgrade which steals life.