Absorb Element

Absorbs a portion of damage from specific element(Fire/Water/Chaos/Shadow):
If a condition(e.g. less than 50% hp or "not in stun/poisoned state") is met, a portion of absorbed damage is added to mana or life.
Skill uses Diminishing Returns formula for percent of absorbed damage:
http://videogamedesign.wikidot.com/mechanic:diminishing-returns