I mean tanks have 300 armor which is like 80% damage reduction. Sure she does true damge but thats every 3 hits, without armor pen her damage should be negligible. but vayne i see chunking tanks apart in about 2 seconds, makes no sense mathematically.
For starters, that vayne was plat 4 and you didn't have much max hp as you went Ravenous Hydra, netting you just under 3000.
Im going to guess you had around 300 armor with base and runes, meaning you take 75% reduced damage.
vayne had ~200 AD with IE and 100% crit, making every auto do around 450 vs 0 armor, so with 75% reduction brings that to 112.5. PLUS Statikk shiv and RFC, meaning when it procs it deals (160*2.5)[its modified by crit chance and crit damage] = 400. You likely had around 54 MR, reducing this damage to about 240. This brings her first auto damage to 350.
Her first 3 autos together do: (113+240)+113+113+(12%*~3000), doing roughly 940 damage. it would take roughly 9 autos to kill you. With vaynes approximate 2.2 attack speed, it would take 4 seconds to kill you.
The math does add up :)
Riot doesnt like tanks dying, but they dislike adcs not 3 shotting even more.
Her ult gives her a ton of AD which then also gets multiplied by Q, which can also crit, which results in very high damage when she does crit
do you not understand how true damage works?
% HP true damage, also 
gives bonus % damage based off HP difference
she has always been known as a tank shredder, same as kog
That's her job.
Tanks need something to be afraid of, what with them doing some of the most damage in entire games while being ridiculous to fight against and kill.
