Reptilian

Reptilian looks like a chameleon scaled up to human size, with dark nails and a ninja getup of dark robe, a hakama with one shadowed fold, long wrist gauntlets, and sandals. His true form is something else entirely, a living castle styled after Matsue Castle, his head perched atop the structure while six muscular reptilian limbs hold the whole thing aloft.

Reptilian's ego is bottomless, and his pride in being a space ninja is so bound up with who he is that being outdone in stealth drives him to fury. Beaten and humiliated by Momo and Bamora using a kaiju suit's invisibility, he refused to credit them as anything more than ninja wannabes. When it comes to missions he calls himself a pragmatist, having argued to Red Baron that killing Momo, Seiko, and Bamora outright and handing the bodies to the Serpo beat any elaborate ruse. Yet once their joint scheme fell apart, he was every bit as eager as his partner to dodge the blame.

The Serpo tasked Reptilian and Red Baron with claiming Momo and Seiko's powers when the group reached Izumo Taisha seeking the Uchide-no-Kozuchi. Reptilian camouflaged himself as a replica of Matsue Castle while Red Baron posed as a shrine priest to draw the targets into the trap. After Red Baron's deception collapsed, Reptilian revealed himself, faulted his partner for not simply killing the targets, and grudgingly used his power to pin Bamora and Momo beneath the castle's lower level while Seiko held off his ninjas.

His squad of ninjas fell one by one to Bamora, who wielded her suit's invisibility for ambushes, and when Momo's aura sensing exposed his hiding spot, Reptilian was struck and humiliated. Enraged at being outclassed in his own craft, he assumed his true castle form. As Momo piloted Bamora's enlarged suit, his kite ninjas kept tracking the kaiju and rained down the explosive Ninja Art: Sakura Riot, draining the suit's endurance until it shrank and collapsed, letting him crow about being the real ninja.

His triumph was a setup. Momo's voice taunted him from nowhere, and she revealed that she and Bamora had snatched the ninjas' explosives and scattered them through his castle body, invoking the Issun-Boshi tale of a tiny hero striking from within. Thrashing in vain to shake them loose, Reptilian could not dislodge the pair who had once clung to a plane through a typhoon. As the two exited his body and Momo readied her Moe Moe Tri-Beam, she ignited the bombs inside him, blasting him apart and ending the fight.