~ Guildenstern sending Marcellus to fight Samanosuke.

Marcellus is a Genma demon and a recurring boss in the Onimusha game series. He is a former Oni Warrior who was captured by the Genma and turned into a Genma by Dr. Guildenstern. Although he still possesses an Oni gauntlet on his hand from his past life, Marcellus is now a mindless super soilder for the Genma army. Guldenstern calls him "My Greatest Creation".


Far before the events of the first game occur, Marcellus's human name was Murokoto, and was a monk and a top warrior for the Oni in their battle against Fortinbras' demon clan. He fought the demons along side his friend and fellow warrior Sougen, and together they won many battles against the Genma army. 

Fortinbras, seeing that Murokoto was a severe threat to him, ordered his most trusted subordinate, Guildenstern, to capture and covert Murokoto to their side. Guildenstern challenged Murokoto to a duel which Murokoto accepted. However, it was actually a trap. 

After Murokoto was defeated, Guildenstern operated and resurrected him, turning Murokoto into an obediant warrior-slave that would do whatever Guildenstern ordered of him. Guildenstern bestowed the name Marcellus on him to symbolize his rebirth as a Genma demon.

Onimusha: Warlords

The protagonist of Onimusha: Warlords, Samonosuke, faces Marcellus in battle twice. He first meets Marcellus on the roof of the castle and is forced to fight him. Marcellus fights with a huge curved sword and metal sheild, and possess an Oni wind ord that controls the power of the wind. Marcellus uses his wind orb to enhance the power of his sword, making it super forceful, often knocking Samonosuke off his feet. 

After Samonosuke defeats him, Marcellus falls backwards off the roof, with the wind orf falling out of his guantlet. Samonosuke takes the wind orb, and utilizes it against the demons.

Later, Samonosuke enters the demon realm. Guildenstern stops him and tells Samonosuke he will not be able to enter. Samonosuke insults Guildenstern, resulting in Guildenstern becoming furious and ordering Marcellus to attack Samonosuke.

After a time of fighting, Marcellus changes his sword and shield into two large swords that allow him to swing and move at high speeds. After he is defeated, Marcellus disappears.

Onimusha: Blade Warriors

Marcellus is a playable character in Onimusha: Blade Warriors.

Onimusha 3: Demon Siege

Marcellus returns in a short appearance in the third Onimusha game. Marcellus in an attempt to prevent one of the protagonists from raching Nobunaga. However, Marcellus is defeated.