[Ivramire]

I was studying items and got some questions x)

I'm confused about what counts as ability power. Actual "nukes" (like... Annie's Q skill) are increased with AP items, but what about abilities that increase attack speed? Do AP items increase the dmg of the attacks, or do they not since they're still.. "regular" attacks?

Unless it's stated in the description, more or less AP doesn't change abilities like those.

AP, defense, attack speed, crits, lifesteal etc stacks, right?Are there any "caps" with the stacking? I'm not talking about the items that slowly increase a stat overtime and "cap" at one point, but I mean in general when you combine all the items together.

There's caps on almost every stat. Some stats don't really cap but do get a lot less effective the more you have of it. I don't really understand the bolded part.

And how do... attack speed/crit/etc stuff stack? Say you got items with 20%, 30% and 40% attack speed. Is that.. +90% attack attack speed or do they take the "new" numbers into account? Like 20% of "base" AS, then it's 30% of the 20% of "base" AS, and so on. @_@

The max attack speed anyone can have is 2.5 attacks per second. Most champions start anywhere from .7xx to .9xx attack speed and the bonuses all add up to base until it reaches 2.5.

Does the CD reduction that comes with some items stack? Do they stack like attack speed?

All the cd reduction from items works together but you can only have up to 40% cd reduction.