What is the point of buying armor?

armor counters lethality not the other way around

at level 18 has the lowest base armor at 68 outside of thresh and mini gnar. With , she has 113. With , you have 39% damage reduction against without , you have about 15% damage reduction against

Without any health items, has 1860 health at level 18. Let's say that the enemy does 3000 damage before reduction. With , they deal 1830 damage. Congrats, you lived. without , they deal 2550 damage. Dang, you died.

That's why you build armor.

So that your hp doesn't go to 0 with your armor

why do we bother building HP? everyone builds a billion damage and get a bunch of random abilities with said damage and just reduce your HP to 0 regardless

If you actually want to know why and not just rant about Lethality http://boards.na.leagueoflegends.com/en/c/gameplay-balance/KxMEsLB9-easy-graph-to-understand-armorlethality

Turns out the difference between having 0 and having double digit effective armor is pretty big when damage reduction scales the way it does.