What we can currently say:
Custom Skins are not bannable and we have not received any user reports yet. Asian servers are different and they are not supported by Fantome or LCS-Manager. Only Garena is supported.
Other SITES that use custom skins:
All programs except for Fantome and LCS-Manager are a risk to your account. Only Fantome by Crauzer and LCS-Manager by moonshadow565 are safe to use. We cannot guarantee custom skins from other websites than killerskins.com will be working with the provided programs or are safe to use, so we do not recommend using custom skins from other sources.
Asian custom skin tools:
Some Asian custom skin tools stole from Fantome and broke the creator’s license. Avoid using them to not risk your PC getting infected with Malware or your League of Legends account being (perma-)banned. We do not support the usage of those tools or Skins (GEZI Skins).
Fantome License – for Fantome by Crauzer and LCS-Manager by moonshadow565
Skin Hacking/Using official League of Legends skins for free:
Skin Hacks = The usage of official League of Legends skins that you have to purchase for RP in the Shop, without actually purchasing them, but modding the files and using them as “custom skins” for free.
Fantome and LCS-Manager do not support using official League of Legends skins for free. No such custom skins will be posted to killerskins.com and the creation of those will not be endorsed in the Killerskins Discord community. If you are using Skinhacks provided from other sources or created on your own, we will not take any responsibility for the safety of your League of Legends account.
Using Riot intellectual Property (IP) from League of Legends and “remixing” them into actual custom skins is legal, as long as they are non-commercial (which they are on this website).