Marco is one of the remaining spirits of the Celestials in the Ark of Yamato. He is also a merchant who trades both Yen and Demon Fangs and also one of the only two merchants who sells the Tundra Beads.
Alas, only my spirit remains in this world. I've been imprisoned here for many years. Perhaps it was my destiny.Marco
200 years prior to the events of Ōkami, the Celestials were living peacefully on the Celestial Plain, but suddenly, True Orochi and its endless legion of demons came and assaulted the Plain and its residents. Following Waka's prophecy, Amaterasu dragged the beast down to the mortal realm, while Waka evacuated the remaining Celestials into the Ark of Yamato, hoping to escape. However, not long after setting sail, an endless legion of demons appeared from the ark's depths, and they slaughtered the Celestial in an event that would be known as the Ark of Yamato genocide. The ark lost its rudder and plummeted down to Laochi Lake, where the demons within the ark disembarked and went on to cause havoc in Nippon.
After the defeat of Lechku & Nechku, Amaterasu and Oki returned to Kamui (Ezofuji), just as Lika finished the Volcanic Incantation. The blade Kutone, which was used to vanquish the twin demons, was returned to its pedestal on the shore of Laochi Lake by Oki's own hands. A golden light suddenly shot forth from the blade, and the perpetual ice of the lake melted as the Ark of Yamato rises into midair. Upon boarding the ark, Amaterasu found Marco at the entrance of the antechamber. He greeted her and offered her to buy his merchandise. Later, after all five of the bosses are defeated in rematches, Marco wishes Amaterasu good luck and bids her farewell one last time before she departs for the battle against Yami.
Marco has the typical appearance of the Celestials. He has a white toga, lush golden hair, a halo and wings on his head. He, like all other Celestials, expresses respect and joy upon Amaterasu's arrival in the Ark of Yamato. He expresses grief when mentioning about the Ark of Yamato genocide, but is also hopeful of Amaterasu's victory, as he wished her good luck just before she departed for the battle against Yami.