Ultraman F (ウルトラマンF Urutoraman Efu) is the third novel from the TSUBURAYA X HAYAKAWA UNIVERSE collaboration series after Return to Tatara Island: Ultra Monster Anthology and Ultraman Dual. This novel serves as an alternate continuity in-between the finale of Ultraman and the beginning of Ultraseven.
It has been a year after Ultraman left the Earth and military forces from around the Earth started to strengthen their forces. A certain country developed giant soldiers and created clone monsters through the enlistment of child prodigies.
SSSP soon created the Ultra Armor based on their studies on Alien Ruperts technologies and the leftover of Ultraman's essence in Hayata.
As the story moves forward, monsters from Heisei Era Ultra Series started to appear. Fuji at the other hand, sensed something strange which was last felt during her kidnapping by Alien Mefilas.
- Akiko Fuji: The novel's protagonist, Akiko is the only one to protest against Hayata's experimentation on Ultraman's essence. She dons the Ultra Armor made by Ide and becomes Giant Soldier F. Her body was revealed to have contain Mefilas Bot, nanobots which was responsible for transforming her into Giant Fuji in the past. These nanobots were deactivated after Mefilas' defeat but during Fuji's fight with Dark Zagi, they were reactivated again and transformed her into a pseudo-Ultraman named Ultraman F.
- Shin Hayata: Originally the main protagonist of Ultraman, Hayata was reduced to supporting character of this novel. In hopes of developing SSSP's military strength, Hayata allowed himself to be experimented in hopes of gathering Ultraman's essence.
- Mitsuhiro Ide: The de facto character of this series, after studying Ultraman's essence, he quickly developed the Ultra Armor.
- Daisuke Arashi: In this novel, he was revealed to be adopted by a family. He has a twin brother named Shigeru Furuhashi, who would join the Ultra Garrison.
- Toshio Muramatsu: SSSP's captain, now serves as the negotiator between UN forces and his own team.
- Ultra Armor: Mechanical armors made by studying Hayata's Ultraman essence and the technologies of Alien Ruperts. These armors resemble the Roman Praetorian guards and soon, larger variants were made by Ide in collaboration to Inpei Sean's Giant Soldier program.
Unnamed foreign country
- Inpei Sean (インペイシャントButterfly Morpho. He soon assisted the SSSP by combining the giant soldier and Ultra Armor technologies.
): The creator of the Giant soldiers, using the essence of
- The Giant: Biological weapons created by injecting soldiers with the Butterfly Morpho's essence. Hayata and Fuji soon injected themselves with it while fighting against Dark Zagi and Beast the One. Unlike Koji (the original giant), the Giant Soldiers were 40 metres height in resemblance to the Ultraman.
- Gomess and Jirass: Inpei Sean's re-manufactured clones of the original monsters with cybernetic remodeling to control their actions.
- Soso (躁躁Dark Mephisto.
): A boy prodigy who created the past monster clones. Both him and Utsutsu eventually defected and joined Dark Zagi in a conquest to become the new rulers of the Earth. He transforms into
- Gomora: Soso's monster clone, created by using its DNA from its defeat by Ultraman in Osaka. The Gomora clone is 4 m short due to being in juvenile state.
- Kemur Man: One of Soso's monster clone created by the same DNA.
- Bullton: Created in secret, Bullton's creation however brings multi-dimensional threats which would soon be Dark Zagi, Beast the One and etc.
- Zetton: Only mentioned, according to Soso, the cloning of said monster was quickly scrapped after finding it hard to be controlled.
- Utsutsu (鬱鬱Dark Faust. ): A girl prodigy who worked alongside Soso and joins him in his defection. Through a deal with Dark Zagi, she transforms into
- Unnamed Marshal: The military leader who is in charge of the artificial monsters made by Soso and Utsutsu. He transforms into Jamila through the leftover of its DNA injected to him.
- Alien Zetton: The true antagonist of the novel, following their failure to use Zetton, they brought Hyper Zetton instead.
- Hyper Zetton: A stronger variant of Zetton brought to the Earth, it was feed with IF in a similar manner to the one from Ultraman Saga with Sphires. Originally in Cocoon state, it was quickly evolved into Imago when SSSP try to attack it with the Pencil Bomb, the same rocket that was used to kill the original Zetton.
- Beast the One: Emerging from a portal, Beast the One started as a 1 gram cell before it quickly evolved into Beruzebua Korone. This monster fought Hayata, who was enlarged and wore an Ultra Armor before it was destroyed by the Pencil Bomb.
- Dark Zagi: A dark giant who strikes a deal with Soso and Utsutsu to conquer the Earth by having them turned into Dark Giants.