The Elder Scrolls V: Skyrim

Mephala's daedric artifact ebony blade. It has a 10 pt absorb health initially and a 30 pt absorb health "fully charged". It is not a conventional enchanted weapon as it never has to be charged with a soul gem, hence the guaranteed 30 health per strike.

There are plenty of topics that go into how to use it effectively and what perks and enchantments actually affect it.