[K]

Lifedrain comes in two flavors: major and minor(its minor unless it says major, in general).

So, minor lifedrain lets you recover up to 10 points of tatigue and up to 2 HPs per hit (5 damage max lifedrain, which is doubled for fatigue and halves for HPs).

Major Lifedatin is on a few artifacts and is doubled for fatigue and halves for HPs(no cap).

Wraith Sword uses minor lifedrain.

Standard of the Damned casts the spell Drain Life. It wokrs like major lifedrain, but with its own spell damage. You don't put it on an SC, but on a commander who spams it (since people in melee rarely cast spells, its not as good).