User blog comment:Kenetron/Evah, the Haven of Justice/@comment-10958553-20140113015009

Holy shit thought that passive. Build berserkers grieves,  blade of the  Ruined King, a nashors tooth, wit's end, a zhonyas and a phantom dancer and you will have.......

180 AP (Im rounding this up to 200 because of runes and masteries) which equals 7% maximum health on hit (assuming level 18) plus 5% current health.

Phantom Dancer gives the player the change to make magic damage critically strike, making the passive have a 30% chance to deal 14% of the players maximum health.

192% attack speed from the items and 72% at level 18 gives you 264% attack speed, or 1.73 attack speed.

The passive alone deals 12% maximum health a second at this point, factoring in the crit chance and the effective damage is 15.743% maximum health a second assuming even crits happen over the durration of your attacks.

Not sure if these numbers are large or small but they need to be considered.