User blog comment:Vectus13/% Health shred option for AD casters?/@comment-6000413-20131205114319

Against health stackers (say 4000 HP), stack penetration. If they have around 150 armor, having BC you can reduce it to 111, then you have yoummu+BC+runes penetration = 10 + 20 + 19 =49, sending them to 62 armor, reducing their effective HPs from 10000 to 6480. To cover that difference you would have to use BotrK's active and add 15 autos. Even if you take into account that you already have penetration runes, you still need 11 hits (and the active) to cover the difference.

And, by the way, if you really need to face huge health stackers, you can pile up these items with BOTRK, so that the active is even more effective and you still throw some autos among your ad-caster combo.

Actually, Rene benefits greatly from BothRK because it applies on one of his abilities and cull the meek, the only one that really has nothing to do with it, has a long CD and lets you auto between uses.

Even Zed can benefit from BotrK, especially if he uses the active right after the ulti. Shadow, ulti, active, shuriken, slash, auto+passive, auto, target dead. If the enemy is full-HP at the beginning of the fight, he receives a total of 22.5% HP form active+extra ulti damage, for a total of 37.5 max hp shred from Zedd (+passive on 2 autos).

In general, every AD caster can use BOTRK for the  active and a couple of autos in-between his rotation