Talk:Essence Reaver/@comment-26837195-20151005121041/@comment-24613667-20151006234309

2 to 8% of the damage you deal is returned as mana based on your missing mana. How much mana you receive per attack is based on a percentage of each auto-attack's damage, the percentage dynamically increases based on how much mana you're missing.

600 damage crit x 2% = 12 mana returned

600 damage crit x 8% = 48 mana returned

There's still some hidden math there (specifically, how much mana must you be missing to reach 8%?, I assume 0 mana), but it basically means you get more mana back the lower your mana gets.