Novel List by Alphabet O
- Obaachan (28) is Free
- Observation Record of a Self-proclaimed Villainess’ Fiance
- Obtaining the Strongest Cheat
- Occupation: Adventurer; Race: Various
- Ochita Kuroi Yuusha no Densetsu
- Ochitekita Ryuuou to Horobiyuku Majo no Kuni
- Oda Nobuna no Yabou
- Oda Nobuna no Yabou Gaiden – Jakigan Ryuu Masamune
- Oda Nobunaga to Iu Nazo no Shokugyo ga Mahou Kenshi yori Cheat Dattanode, Oukoku wo Tsukuru Koto ni Shimashita
- Offer to the CEO
- Official Savior
- Oh My Ice Goddess
- Oh no! After I Reincarnated, My Moms Became Son-cons!
- Ojamajo Doremi 16
- Okoborehime to Entaku no Kishi
- Old Vampire and a Holy Girl
- Omae Mitai na Hiroin ga Ite Tamaruka!
- Omae o Otaku ni Shiteyaru kara, Ore o Riajuu ni Shitekure!
- Omae wo Onii-chan ni Shite Yarouka!?
- Omni Genius
- Omni-Magician
- Omnia wo Suberumono
- Omnipotent Sage
- Omniscient Reader
- On the Way Home I Got a Bride and Twin Daughters, Who Were Dragons
- Onani Master Kurosawa – After the Juvenile
- Once Promised
- Once Upon A Time, There Was A Spirit Sword Mountain
- Once We Come Across Love
- One Child Two Treasures: The Billionaire Chief’s Good Wife
- One Hundred Stories
- One Life, One Incarnation – Beautiful Bones
- One Man Army
- One Night, One Day, One Year, One Lifetime
- One Piece System In One Piece
- One Piece: The Soul Purchasing Pirate
- One Sweet Life
- One Sword to Immortality
- Onegai Twins
- Ongaku no Shinigami
- Onii-chan Dakedo Ai Sae Areba Kankeinai yo ne
- Online Game: Evil Dragon Against The Heaven
- Online Game: Willingly Captured
- Only I Am Not Attacked In A World Overflowing With Zombies
- Only I Shall Be Immortal
- Only Sense Online
- Only Starlight
- Ookami Kodomo no Ame to Yuki
- Ookami to Koushinryou
- Ookura Teruko Detective Story Compilation
- Ordinary I and Extraordinary Them
- Ore Dake Kaereru Kurasu Teni
- Ore ga Heroine o Tasukesugite Sekai ga Little Mokushiroku!?
- Ore ga inmajutsu de dorei harem wo tsukuru hanashi
- Ore ga Inmajutsu de Dorei Harem wo Tsukuru Hanashi
- Ore ga Isekai Dungeon da! – Tensei Shitara Karada ga Dungeon to Kashiteita
- Ore ga Ojou-sama Gakkou ni “Shomin Sample” Toshite Rachirareta Ken
- Ore no Imouto ga Konna ni Kawaii Wake ga Nai
- Ore no Isekai Shimai ga Jichou Shinai!
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore no Nounai Sentakushi ga, Gakuen Rabukome o Zenryoku de Jama Shite Iru
- Ore no Ongaeshi: High Spec Murazukuri
- Ore no Osananajimi wa Joshikousei de Yuusha
- Ore no Sekai Kouryakubon!
- Ore to Kanojo no Moe yo Pen
- Ore to Kawazu-san no Isekai Hourouki
- Ore, Twintail ni Narimasu.
- Originally, I Was A Delinquent, But Now I’m A Serious Girl!
- Orihara Izaya to, Yuuyake wo
- Ostentatious Zhao Yao
- Other World Assassin Life of a Man who was a Shut-in
- Other World’s Monster Breeder
- Otherworld Nation Founding Chronicles
- Otherworldly Evil Monarch
- Otherworldly White Dragon Lord
- Otoko Nara Ikkokuichijou no Aruji o Mezasa Nakya, ne?
- Otome Game no Akuyaku Reijou o Tanoshimitai!
- Otome Game no Akuyaku Reijou o Tanoshimitai!
- Otome Game Rokkushuume, Automode ga Kiremashita
- Otome Nadeshiko Love Diary
- Ototsukai wa Shi to Odoru
- Ou-sama Game
- Our Glamorous Time
- Our Goddess
- Our House Pet
- Our Journey
- Our Second Master
- Outbreak Company
- Outcast Magician And The Power Of Heretics
- Overgeared
- Overlord (LN)
- Overlord (WN)
- Overlord, Love Me Tender
- OverPowered System
- Overthrowing Fate
- Owari no Chronicle
- Owari no Chronicle DC
- Owari no Seraph
- Oyaji Kanojo