Originally Posted by Alkorin
How do you counter Black Cleaver, building more armor which is just going to be negated anyway?
In most games I'd say the counter is probably going to be more champion-centric than anything you can do with items. Most of the champions that stack Black Cleavers are ones that dive into the middle of a team or pick off priority targets that are straggling.
The best way to counter divers is just with ridiculous amounts of CC. When a competent Alistar or Nautilus is nearby, diving to their buddy is more or less impossible. Sticking together also helps, Bruisers in general excel at 1v1 duels - so they'll destroy pretty much any champion in a 1v1 regardless of how many Black Cleavers they may or may not have.
Also, if you can get a tank that actually has a solid defensive steroid the armor penetration won't be that impressive. Alistar's 70% damage reduction doesn't care about how much armor penetration you have, and Malphite's 40% armor booster will pretty much erase any benefit from armor penetration against him.
For items I'd say things like Frozen Mallet and Rylie's Crystal Scepter are probably the best counter-building options. You get plenty of HP to survive the burst rotation, and kiteability to survive the journey to better positioning - or get that Cleaver Stacking fiend stuck in a bad spot long enough to take significant punishment for jumping on your face. Gap closers are cool and all, but mostly solve the problem of being melee once - not indefinitely.