Maas Simeon is a character from the anime film Mobile Suit Gundam SEED FREEDOM, originally introduced in the television series Mobile Suit Gundam SEED Destiny. He is a Coordinator, a genetically enhanced human, and a former pilot of the ZAFT army. He continues to wear the green ZAFT uniform in the film. Simeon belongs to a trio of soldiers who are part of the Clyne Faction, a group loyal to Lacus Clyne. Alongside his teammates Hilda Harken and Herbert von Reinhard, he pilots the Dom Trooper mobile suit, a heavyweight machine that the trio uses to execute coordinated trinity attacks in combat.

Personality-wise, Simeon is described as having a tough and straightforward demeanor. His motivations are rooted in loyalty to the Clyne Faction and its goals of peace and stability. He serves as a supporting pilot within the organization Compass, a world peace monitoring group formed after the conflict. In the story of Mobile Suit Gundam SEED FREEDOM, Simeon participates in operations alongside other Compass members but ultimately meets his end in battle against the elite Black Knight Squad. His key relationships are with his teammates Hilda and Herbert, as well as his allegiance to Lacus Clyne. Simeon does not undergo significant personal development in the film; his role is that of a capable but minor supporting fighter who contributes to the larger conflict. His notable ability lies in his skill as a mobile suit pilot, particularly in coordinating with his teammates to maximize the effectiveness of their heavyweight Dom Trooper units in battle.