TV-Series
Description
Gilmer is a Decepticon Pretender who crash-landed on Earth millennia ago alongside Blood and Dauros, fleeing Autobot pursuers led by Metalhawk. Adopting monstrous Pretender forms to terrorize early humans, Gilmer's aquatic assaults on ships and domination of underwater realms inspired ancient sailors' tales of sea creatures. His aquatic form enabled him to generate undersea volcanoes, command sea life, and manipulate ocean currents with his "Aqua Saw" sword. Following epochs of conflict, Autobots defeated and imprisoned the Decepticon Pretenders, sealing Gilmer within Atlantis' ruins.

Freed in the present era by the energy entity Devil Z to advance its schemes, Gilmer displays a pragmatic and somewhat resigned personality, acknowledging he is older and less driven than his fellow Pretenders. He maintains functional relationships with Blood and Dauros, scheming with Blood and undertaking missions with the combative Dauros, who shows him respect. Gilmer frequently mediates conflicts between Dauros and Blood, often stemming from Dauros's resentment of Blood's leadership.

Gilmer participates in numerous Decepticon operations: attacking maritime vessels to lure Autobots, stealing corpses to create unstable "Destroid" zombies, capturing human test subjects in the Karin Islands, and unleashing the Decepticon Headmaster Juniors in Tokyo. He later engages in destabilizing activities like causing animal stampedes in Africa. His combat effectiveness is greatest in aquatic environments, leveraging his purple Cybertronic submarine alternate mode—capable of hovering over land—and his mastery over water.

As Devil Z's forces expand, Gilmer and the Pretenders fall under Godmasters Giga and Mega's command. He resents Mega, making disparaging remarks about her leadership; she overhears and punishes him by forcing him to act as a training dummy for the Headmaster Junior Cancer. Gilmer's attempts to regain favor often fail, such as discovering the Autobots' secret British Motors project only for Hydra and Buster to coerce the information and claim credit. His participation in the subsequent attack results in severe damage, with Gilmer and his comrades losing limbs against Autobot Godmasters.

Gilmer continues activities like aiding in the capture of doctors worldwide and searching for the final Godmaster, Clouder. He is last seen fleeing with other Decepticons after Devil Z unleashes wrath upon the failing Hydra and Buster. His ultimate fate is unresolved, with no confirmation of joining Overlord's space-bound Decepticons or remaining on Earth after Devil Z's destruction.

In non-anime media, his toy was marketed as "Submarauder" in Western regions. The figure transforms into a submarine and features a monstrous Pretender shell with gills, scales, and a dorsal fin, wielding a sword and gun. An Italian dub renamed him "Reptilo".