Comprehensive Anime: I'm Rias's Childhood Friend

Mori Ayato traveled to a comprehensive anime world and became Rias Gremory's childhood friend. He also changed his class to become an Origin Magician, continuously growing stronger as long as he gained knowledge. He even created Otherworldly Devil Contracts, extending his reach into countless worlds and recruiting servants. ...... Rias: Ayato is my fiancé. Utaha: Master, I want to replenish my magic again. Asia: As long as I can help Ayato-san, anything is fine. Akame: Master, want some meat? ...... Before he knew it, Ayato was already capable of slaying gods. --------------------------------------- — Description from novelcodex.org