“I shall explode the crude human concept of emotion. This is the next step in humanity's evolution!”
- ― Gelimer, before preparing to drop his bombs onto Edelstein
Gelimer was a scientist of the Black Wings and head of the organization as well as a Black Mage Commander. He is the main antagonist during the Black Heaven storyline and the inventor of the eponymous airship.
In the game, he revived Orchid's twin brother Lotus. However Gelimer used Lotus, who was under his control, to attack Orchid and stage a coup in the Black Wings. Lotus left her for dead in an alley, but the Resistance found her.
50 years before the events of the story, Gelimer was friends with a younger Irvin and Martini, the latter of which would end up working for him in the Black Wings organization. Gelimer was a genius scientist in Edelstein who specialized in medicine and biotechnology and did not seem to have an interest in robotics and machiniery at all. All of Edelstein had high hopes for him. Eventually, he and Martini would stoop low in human ethics and experiment on human subjects, which disgusted Irvin.
Gelimer kidnapped a child (who would be later be Xenon) and made him into a killing machine. He believes emotions are a weakness, and does his best to destroy any robots that show signs of developing them. (Ironically, in Black Heaven, the player gains invaluable help in boarding the giant craft from One-Eye and Three-Hands, two robots who did develop emotions but escaped this fate.
He sees little in the value of life and would do experiments on even baby animals if it meant furthering his goals. The player notices his callous tendencies early if they accept a quest that requires the player to take a core from a robot with evolved emotions; doing so would eventually kill her. Said robot's "brother" is able to save her by giving the player his core, and another robot is able to replace that robot's core with one he made for that exact purpose. Gelimer clearly knows how the player got the core when given it, but it makes no difference which one he gets; he just doesn't care.
In the final chapter of the Zero storyline, he and the other commanders are there talking to Alpha and Beta, where he is seen standing next to a brainwashed Lotus.
In the Black Heaven storyline, he says in that his goal is to eliminate all human emotion and make everyone in Maple World his puppets. This could mean that serving the Black Mage and planning his resurrection is only a minor goal or not one at all. In the sixth chapter, he is depicted as a sadist, mercilessly taunting and goading the player and other Alliance members, eventually cruelly eliminating Lotus for failing him, and then, at the climax, poisoning the player's character in an ambush.
Unfortunately for him, he is done in by his own cruelty. By killing Lotus, Orchid gained his powers, allowing her to save Edelstein from Black Heaven's bombs. And shortly afterwards, after setting his Xenoroids to self-destruct, he attempts to escape, only for the Xenoroids to latch onto his escape pod and beg their "father" to take them with him. The player uses the last of his/her strength to launch Gelimer and blow him up in midair; he perished in the explosion.
- If the player is using one of the Resistance classes during Black Heaven when he/she confronts Gelimer, he/she angrily curses him for Vita's death, only for Gelimer to reply that he doesn't even remember her, coldly showing how callous he is towards human life.
- Also provides the voice(s) of Xenon, Checky, Grand Master, and Aaron (Gerand Darmoor).
- Also provides the voice(s) of Mihile (Job), Eckhart, Von Leon, Neinheart (Cygnus Returns video), Stan, and Ericsson.
- Also provides the voice(s) of Luminous, Black Mage, White Mage (MapleStory Black Mage Prologue "Origins"), Freud (Shade cutscene), Damien, Elite Bosses (Black Knight (Hardin), Mad Mage, Rampant Cyborg (Quieg), Vicious Hunter, Bad Brawler), Grendel the Really Old, Melange, Sharen III, and Ergoth.