Ryoan is a Buddhist monk offering guidance and support to protagonists Ayame, Sakon, and Ryoma on their journey. He aids them with chants and knowledge, appearing at crucial junctures to assist their quest against Oda Nobunaga's demonic forces.

Unbeknownst to all, Ryoan possesses a hidden identity as one of the Host of Oboro, supernatural ninja serving the antagonists. This secret remains concealed from both himself and the protagonists for much of the story. Despite his true nature as Oboro, his actions consistently support the heroes against the demonic threat.

Ryoan meets his end during the final confrontation when the primary antagonist, Ranmaru, impales him with a piece of wood. This fatal intervention occurs as Ryoan continues his efforts to aid the protagonists against the demonic forces. His death eliminates a key ally for the main characters during the climactic battle at Azuchi Castle.

Visually, Ryoan wears traditional monk attire, including a distinctive hat and kimono. This design inspired later anime characters, notably Dakuan from *Ninja Scroll*, who shares similar apparel and narrative functions.