One of the engimatic "Olympus Twelve", it is a Digimon god of war in the shape of a panther-man. The Olympus Twelve are guardian deities of the Net possessing ability rivaling that of the Royal Knights, and while they guard the same area, they are seen to have come to follow independent views regarding the occurrence of disasters in the Digital World. Marsmon is familiar with all the ways in the world to fight dirty without weapons, but at the same time he possesses absolute self-confidence regarding bonding through one-on-one combat. It makes use of basic wrestling techniques, but it is strongly concerned about victory and glory, so when push comes to shove it won't hesitate to use concealed weapons like its "Toria Knuckle" or "Metal Korutonosu". However, it exhibits its real power when it uses its bare hands and feet. Its Special Move is a method of magnificently splitting the sky while clad in flames (Corona Sanctions).

謎の集団“オリンポス十二神族”の一人で、豹人の姿をした軍神デジモン。オリンポス十二神族達はネットの守護神“ロイヤルナイツ”に匹敵する能力を持ち、互いの領域を守りつつデジタルワールドで起きた事変には中立の立場を守ってきた影の存在であった。マルスモンは世界中の反則技を含む全ての格闘技に通じ、同体重同士の一対一での戦闘には絶対の自信を持っている。基本的にはレスリング系の技を用いるが、勝利と栄光に強くこだわるマルスモンは、いざともなればためらうことなくトリアナックルやメタルコルトノスの隠し武器も使う。しかし、真のパワーが発揮されるのは素手・素足になってから。必殺技は炎をまとった華麗な空中殺法『コロナサンクションズ』。