Epsilon masterminded the revolt on Gigantis Island and is the leader of the Rebellion Forces. Proud and relaxed, he is usually very stoic and quiet, his presence accentuated in this vein by his unprecedented (for a Reploid) African features. Epsilon was the only Reploid to survive the Supra-Force Metal infusion experiments, giving him heightened intelligence and strength capabilities. All other volunteers in the experiment either went mad (Maverick) or perished outright. Though Epsilon retained his sanity, he realized he could try to reproduce the same results that he had on other Reploids, and thus staged a revolt for Reploid freedom, believing that Reploids could evolve past what humans had made them to be, and become more advanced.
Throughout the game, Epsilon makes attempts to control Giga City's resources while crushing the Resistance that opposes him. Realizing he needs force to make others listen to his ideals, he resorts to creating a missile armed with Supra-Force Metal to keep his foes at bay. Eventually, X and his team make their way into his fortress to confront him. After Scarface falls in his name, Epsilon takes them on himself only to lose. He then stated that his motivations for creating the Supra-Force metal was to have the power to ensure a Reploid-only nation was created, as they were left with no other options due to the Federation branding them as Mavericks. As he tries to continue fighting, X brings him down with his buster.
After the end of the game, Epsilon was deferred of all Maverick charges posthumously, most likely due to the restraint he showed in not killing any innocents during his activities (having banished the humans from Giga City without harm, simply forbidding them to return) and the fact that his whole Maverick status came about as a result of Redips' manipulation of events.
- Ultra Giga Fire - Inflicts fire damage on all party members.
- Ultra Giga Blizzard - Inflicts ice damage on all party members.
- Ultra Giga Thunder - Inflicts electric damage on all party members.
- Power Virus - Inflicts virus status on all party members.
- Fatal Attack - An energy attack that deals tremendous damage on a single target. 100% chance of critical hit.
- Metacrush - Reduces a single target to minimum life energy.
- Nova Impact - A blast that deals high damage to all party members.