RIOT - Why is custom skins not allowed "anymore"?
Custom skins have been a huge part of the League of Legends community and some have even been made into real skins. The creators of these skins have spent hundreds of hours passionately designing skins for no benefit other than the enjoyment of making them for the community.
"Riot has stated in the past that they allow custom skins to be used as long as they are appropriate and are not direct copies of skins that they have already created."