The Disciple of Lich

The Disciple of Lich is a Manga/Manhwa/Manhua in (English/Raw) language, romance series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.com fastest updating comic site. The Summary is

A generic typical isekai manga with a white super-op loli tsundere saves and helps our poor MC after he unintentionally leave his cat and got isekai'd by green-haired god made by superior gods and he/she (idk its gender cuz its god) threw him into the most dangerous labyrinth called 《Cocytus》because our MC offended him.