|“||Maggots like you will burn in hell!||„|
Guildenstern first appears in Onimusha: Warlords. When the protagonist, Samanosuke, meets him, it is obvious that Guildenstern is very arrogant. Guildenstern then unleashes his newest creation on Samanosuke to kill him.
Throughout the game, the player finds books written by Guildenstern that develop the plot of the game. It is revealed that Guildenstern is one of the highest ranking Genma demons. While the vast majority of demons are relatively unintelligent life forms, Guildenstern is not only intelligent, he is a genius among geniuses. The texts reveal that Guildenstern was solely responsible for resurrecting the warlord, Nobunaga Oda . It is also revealed that Guildenstern is aiding the demons in planning “The Dark Ceremony”, which through human sacrifice and demonic arts, will grant Nobunaga more power.
Guildenstern appears in person two more times. He is first shown shortly kidnapping Princess Yuki. He then appears at the end of the game taunting Samanosuke. When Samanosuke insults him back, Guildenstern becomes infuriated, and unleashes his “greatest creation ” to fight him. He then disappears without ever personally fighting Samanosuke.
Onimusha 2: Samurai's Destiny
Although Guildenstern does not appear in person, he is mentioned many times within texts in the game
Onimusha: Blade Warriors
Guildenstern is not a playable character or boss in Onimusha: Blade Warriors. However, he does have a major role in the game. Guildenstern is shown orchestrating the Genma invasion of the human world. He issues orders to all the Genma soldiers to destroy both Oni warriors.
Onimusha 3: Demon Siege
Guildenstern is also a major villain in the third Onimusha game. He is personally responsible for the Genma invasion of France. He time travels from feudal Japan to France in 2004.
He is forced to face Samanosuke again, this time in France. Guildenstern decides to fight Samanosuke personally. However, he is finally killed by Samanosuke.