Transmigrated I decide to save the world from the 7 Hellguardians

After dying at the age of 20,Nyx Ackerman was reincarnated in another world which went by the name Theos . After 27 years of living with many identities and adventures he gets bored of it and decides to become the teacher at the best academy in the floating island Leviathan being the capital of the empire Immorra . 'Why does shit go down when I wanna live a casual and a carefree life'. Later on the the seven HellGuardian's each with their own unique power would be introduced and the mc is forced to fight them of and later confronts the Demon god. The Mc is a Casual person who does not like to kill and prefers it as a last resort .He is mature and a jack of all trades in terms of character and powers(literally) The world building/info dump is very less at the start and will be done at steady paces every 10-15 chapters. This is my first time writing a book so please be a bit lenient English is not my first language so please go with average expectations for grammar