Age: 14 (beginning of series)

Birthday: April 2

Marcus Damon, is a fictional character in the Digimon Data Squad series. His name, Masaru, means Victory in Japanese. He is the first human lead of any Digimon serial, excluding C'mon Digimon, that doesn't wear goggles. Marcus is also the first human protagonist to physically hurt Digimon on a regular basis.

Marcus is presented as a fourteen year-old student who loves to fight. He lives with his mother and younger sister Kristy (Chika). Marcus meets and fights Agumon in the first episode of the series. When the fight ends in a draw, Agumon agrees to become his partner. Soon afterwards he's recruited as a member of D.A.T.S. As Marcus's partner, Agumon idolizes him and refers to him as his "aniki" (a Japanese colloquialism for "older brother," used in this case with the connotation of "boss" as seen in the Yakuza).

Marcus is one of the few humans shown to fight Digimon by himself, though he still counts on Agumon's help to fight the stronger opponents. Even though other humans can evoke their DNA charges by themselves, Marcus must usually connect a punch on an enemy to do so, subsequently using it to digivolve Agumon.