Nephenthes Inhumanoid is a monster serving under Kamen Rider Bujin Gaim that consumed anything that Bujin Gaim wanted out of the way by lifting the flap on it's chest.
The Inhumanoid first appeared in Wizard's part of the movie, where it appeared out of a Crack and devoured a unsuspecting Kosuke, who was holding onto Haruto's WizarSwordGun, then retreated back to its side of the Crack after Bujin Gaim arrived, with the Crack closing with no resistance.
In Gaim's part of the movie, it arrived from a normal Crack at the Armored Rider Battle Royale, and edged closer to Mai. It was stopped, however, when Ryugen shot it in the back, and Gaim following it up in close quarters. Ryugen tried Gaim's tactic, only to get batted aside. With Baron up, the Armored Rider sent it sprawling back, making the Inhumanoid run back into a Crack that spawned nearby, with the three Armored Riders hot on its heels.
He later reappeared on Bujin Gaim's orders and devoured Bujin OOO during the fall of the OOO Army after Bujin Gaim weakened the Bujin Rider with a Blood Orange Naginata Musou Slicer, having already devoured Bujin Wizard, and later Bujin Double in Xtreme Form thanks to some unintended assistance from Zangetsu. When he and Bujin Gaim tried to attack Zangetsu, the Armored Rider easily avoided harm and ran off.
Later, the Nephenthes Inhumanoid devoured Bujin Fourze after he and Bujin Gaim tag-teamed him into submission, then Ryugen after the Armored Rider saved Ieyasu from getting killed, but not before giving Kouta a Suika Lockseed before his consumption, allowing the Armored Rider to use Suika Arms to fight Bujin Gaim and the Inhumanoid off long enough for Gaim to run off with Ieyasu in Odama Mode.
Seething from Gaim running away, Bujin Gaim's special Cracks opened to show the battles between Kamen Riders Wizard and Wiseman, and Kamen Rider Beast and Ogre. Mistaking these Riders as Bujin Riders, he ordered the Nephenthes Inhumanoid to attack them, which would result in Kosuke getting devoured.
The Nephenthes Inhumanoid later jumped out of a special Crack right in front of a Baron Army (formally the OOO Army until Kaito took control of the remnents after Nobunaga's death) jeep, and grabbed Mai. Following hot on his heels, however, was the main world Wizard, shooting the Inhumanoid off of Mai and demanded Kosuke back. The Inhumanoid instead went on the offensive and the Rider and Monster did battle until it ran off after getting roasted from a Special spell.
The Nephenthes Inhumanoid and Bujin Gaim used the energies of the defeated and devoured Bujin Riders onto a prayer tree, making it sink into the ground, only for it to reemerge in the castle of the Wizard Army.
The Nephenthes Inhumanoid reappeared to assist Bujin Gaim fight Gaim and Baron to ensure his master's plan of obtaining godhood, beliving Mai to be the Miko of Fate and the energies of the defeated Bujin Riders, only to be shot in the back by Wizard, who appeared to even things out, isolating the Inhumanoid from Bujin Gaim. When the Inhumanoid tripped Wizard, Baron and Gaim arrived to help out after Zangetsu decided to attack Bujin Gaim, with several slashes to the abdomen being enough to free Mitchy and Kosuke.
When Bujin Gaim tried to run to the tree that grew from below the Wizard Army Castle to grab his godhood, the Nephenthes Inhumanoid ran interference to bide time, with Beast, Ryugen, Baron, and Zangetsu staying behind so Wizard and Gaim could go on ahead. When they took their fight to a nearby plain, Bujin Gaim assumed Lotus Position, and summoned an army of monsters, which then began to congregate to the four Riders and assist the Inhumanoid, and are treated to the sight of the real Miko of Fate after Wizard and Gaim were ejected out of the castle.
After the Armored Riders assumed their Legend Rider Arms forms with Beast going Hyper, Ryugen, Baron, and Zangetsu cleaned house, ridding the area of the monster infestation, with only the Inhumanoid being left, and it was soon destroyed by the four Riders's Rider Kicks.
- Though not known to be an Inves, the Nepenthes Inhumanoid's plant motif fits in with the fruit motif of Kamen Rider Gaim.