IS using mklol for skins alone against the tos?

Yes. If the program has any features that are against the ToS, having it in any way is a bannable offense. It doesn't matter if you don't use those particular features, so please remove it from your computer before you get permabanned.

Please read this reminder from Riot Cluvie for more info; http://boards.na.leagueoflegends.com/en/c/miscellaneous/5kx4F7VE-reminder-third-party-applications

if you want to use custom skins, use wooxy. as you can see from the comments below, wooxy is a safe one because it's ONLY FUNCTIONALITY is custom skins. mklol has features that are against the terms of service, whether or not you choose to use them is irrelevant, riot will assume the worst and you will get caught.

Thanks for the Clarifications guys. And thanks for tip on Wooxy. I didn't install it on my computer yet, i was just curious.,