Ultraman Sisters (ウルトラマン妹 Urutoraman Imōto) is a light novel series. Yuuji Kobayashi (from Ultraman Mebius and Mega Monster Battle: Ultra Galaxy Legends The Movie) is the main writer.
One day, a brother and sister pair came to visit an observatory. The brother, Shota Tsukishima was a 20-year-old without a job and was there in order to be interviewed for a position as temporary worker. Hikari Tsukishima, his sister came along for the interview with her brother and also for a tour of the observatory.
While leaving the building was attacked by an invading monster from outer space. At that time, Shota was wrapped in pink light. From the light Shota heared a girl's voice saying "Please lend me your body" but the being of light noticed that Shota was a man, and it instead merged with his sister to defeat the monster.
- Akari Tsukishima: Junior high school sophomore. Dubbed a "space geek". She is the host to Jeanne.
- Syouta Tsukishima: A 20-year-old. After graduating from high school, he has been on a job search, but has been denied by 30 companies in a row.
- Jeanne: A member of the Space Garrison Force who came to Earth for training from the "Land of Light" (A.K.A. M78 Nebula). She is in fact an apprentice from training school and also happens to be a clunker.
- Kisaragi Yuki/Amur: A member of the Space Garrison Force in charge of global security. The self proclaimed "little sister of Zoffy", she was dispatched to Earth on the orders of Zoffy to be the immediate supervisor of Jeanne. Unlike Akari, Yuki is the result of Amur mimicing a human form. She usually works as an active member of the Earth Defense organization BURK.
- Miya Tachibana: When Syouta was in 5th grade, Miya was a transfer student in the same class for a short period of time. She suddenly appeared in front of Syouta as an official member of BURK. She is really the Higher-Dimensional Life form Alien Ihaton, who stole the real Miya's identity. The real Miya died two years ago in a car accident.
- Sanae Kuroda: Akari's Homeroom Teacher. A well respected 20 year old. She is really possesed by Alien Campenalla as she targets Akari.
- Primitive Space Life-Form Guranbon: An irregular organism that absorbs both organic and inorganic materials. It was at the observatory where it became an octopus like monster from absorbing plants hanging from the ceiling.
- Mimicry Majin Alien Campenalla: A reptillian alien figure that tried to steal the Jeanne Spark by controlling Hikari's homeroom teacher
- Dark Machine Beast Gauche Don: A mechanical monster sent by Alien Porano. Appears in Shota's dream.
- Ultra Science Phantom Alien Porano: Sent Gauche Don, they only appeared in Shota's dream.
- Rock Bird Jobandon: A monster with demonic wings and a sharp beak. Its weakness is an an aneurysm on its back.
- Higher Dimensional Life Form Alien Ihaton: Unknown invaders who have destroyed many worlds but have never once fought an Ultra Warrior. They embody the negative desire of organisms to destroy civilizations. Behaves like a Yandere.
|Showa||Ultraman (Novel, Umezu, Kazumine) | Ultraseven (The Targeted Town Novel, Kuwata, Kazumine) | Return of Ultraman | Ultraman Great Fierce Battle | Ultraman Ace | Ultraman Taro (Uchiyama, Ishikawa) | Ultraman Leo | Mirrorman | The・Ultraman | Ultra Brothers Story | The☆Ultraman | Ultraman 80 | Decisive Battle! Brothers|
|Heisei||Ultraman Great (Manga, Novel) | Ultraman: Super Fighter Legend | Heisei Ultraseven (EPISODE: 0, EVOLUTION) | Ultraman THE FIRST | Denkou Choujin Gridman: The Demon King's Counterattack | Ultraman: The Next | Ultraman Nexus | Ultraman Story 0 | Ultraman Max | Ultraman Mebius (Anderes Horizont, Fight! Ultra Brothers, Armored Darkness) | Mega Monster Battle: Ultra Adventure | Ultra Monster Kattobi! Land | Ultraseven X | Ultra Ninpocho | Ultraman Super Fighter Geki-Den | Ultra Idemitsujin | Ultraman Sisters | Ultraman: Another Genesis | ULTRAMAN | Seven Queu: Lovely Idol | Ultra Monster Anthropomorphic Project (Novels, Galaxy Days, POP, Ultra Journey) | Ultraman F | Ultraman Dual | Mountain Peanuts | Ultraman Dual 2 | Ultraman Orb Chronicle | Ultraman R/B Novel | TDG: Adventure in Hyperspace | Ultraman Tiga: To the Shining Ones | Ultraman Tiga Novel: Forest of the White Fox | Ultraman Dyna Novel: Star of Peace・The・Other|
|Reiwa||SSSS.GRIDMAN NOVELIZATIONS | Hime and Samurai | ULTRAMAN SUIT ANOTHER UNIVERSE | Ultraman Dyna: Zero Drive Towards Tomorrow | SSSS.GRIDMAN ANOTHER LOAD|
|Foreign||Ultraman G | Ultraman: Negative One | Ultraman Tiga | Redman|