Supernatural

No One on Titan

Onegai, Nugashite.

Onijari

Oroka na Tenshi wa Akuma to Odoru

Oswald the Overman in the Lesser Planes of Hell

Raul and The Vampire

Raul to Kyuuketsuki

Rebirth in the end times: I reached the top by opening boxes

Rebirth of King Zhou: Not Being the Ultimate Villain

Reborn as a Demonic Cultivator, Picking Up a Zombie Planet at the Start