BLADE OF THE RUINED KING on Caityln ???

It's necessary when you're against a lot of tanks. Some people would actually rush the BORK then LW, but personally I think it's fine to get IE first and then get them 2nd and 3rd.

Against health stacking tanks yes. Or dive heavy comps that can actually get to the back lines. But if you're against a tank who, for whatever reason, isn't getting health. Don't bother.

Many times, people got annoyed with me for NOT building that (and focusing on damage and critical chance instead) when I was playing Caitlyn in ARAM.

Look here though: http://www.lolpro.com/guides/caitlyn#520099

no one uses it

If there are tanks with health, get BoRK, if you're against tanks with armor, get LW. If you're against tanks with MR, ???

Attack speed Cait is pretty good.

Cait works pretty well with attack speed. IE + PD + BotRK + Last Whisper is an excellent build on her, especially if you're against a cinderhulk toplaner and cinderhulk jungler or a chogath mid.

botrk is so good you can buy it even on support and some ap mid like diana. if you dont buy botrk you are very noob.

cinderhulk and botrk are the 2 most opest item in the game.

other strong item are support item.

others item are shît.

It's ok against divers like Jax

I get it all the time on her lol.