Marcellus is a demon boss from Onimusha: Warlords. He was once an Oni Warrior that converted into a Genma through Guildenstern's experimentation. This engineered demon, created from materials fetched from the Cave of Treachery, is Guildenstern's pride and joy. He wields a weapon resembling the Oni Gauntlet on his right arm.


Over a 100 years ago during the prolonged brutal warfare between the saintly Oni Race and evil Demon/Genma Clan, the Oni War, Marcellus, a warrior monk formerly known as 'Murokoto', had long been a legendary Oni warrior who fought along side another Oni warrior called Sougen in this prolonged brutal battle, earning his glory of his unique combat-skill by striking fear into the heart of every genma battalion with his possession of the bestowed divine orb of wind element: Arashi.

His existence now perceived a threat to the Demon Clan, which caught the attention of the Demon Lord-Fortinbras and his trusted minion-The Demon Scientist Guildenstern, who then plot the treachery. This resulted in the horrific demise of the Oni Warrior, when he accepted the duel challenged by Guildenstern, which turned out to be a setup by the demon scientist himself. However, Murokoto's soul wasn't put to rest for good.

Murokoto's lifeless corpse eventually fell into the hands of the genma's clan. Thanks to the plotting scheme of the insidious Guildenstern, Murokoto's corpse was experimented on and eventually resurrected into a mindless undead, only doing bidding to the Demon Lord. He was then renamed Marcellus, which means 'Ultimate Warrior Of The Genma's Legion', and was the most valuable asset of the genma clan who manipulated Marcellus against his own race, his former allegiance-The Oni Clan.

Onimusha: Warlords

Marcellus makes his debut by battling Samanosuke Akechi in 'Onimusha: Warlords', as ordered by Guildenstern himself, however, due to Samanosuke's persistence, Marcellus was eventually defeated and vanquished, and his warrior orb of wind: Arashi, was ultimately retrieved by Samanosuke. Nonetheless, he was resurrected again with new powers, but Samanosuke comes out on top and he was defeated once more.

Onimusha Blade Warriors

Guildenstern creates and sends various creations to the human world, including Marcellus. During the story-mode, Marcellus past is reveled by Kaede to Keijiro Maeda.

Onimusha 3: Demon Siege

During the time of Onimusha 3: Demon Siege, Marcellus, however, was revived again, but he is much weaker compared to his former self. He was encountered twice by Jacques Blanc, who tried to halt him by reaching the new genma lord: Oda Nobunaga and was eventually defeated in their duel.