|Full name||Kaga Ryosuke|
|Eye color||Olive Green|
Ryosuke Kaga (加賀 良介 Kaga Ryōsuke?) is the main protagonist of the story. He's a perverted second-year student at Momozomo Academy who uses his perverted spirit-energy to give Lisara energy. He also learns from Lisara that he will die in three months, and it is in exchange for his help that she tries to alter his fate. Lisara uses the Broken Sword, Gram, which used to belong to the God of War, to form a contract with Ryosuke. However, it was revealed later that Ryosuke has the other half of Gram (which was thought to be lost), thus gaining full power of the sword. He is in love with Lisara, and can only fully charge his perverted spirit energy if it is her body alone or with his "Invisible Dictionary." He lives all by himself (until Lisara moved in) while at the meantime his mother works overseas in germany and sends him money from time to time. His mother told him that his father died when he was a kid, however this is a lie. His father is actually Galdarblog, and he left with no trace and his mom, not wanting to hurt him; lied.
He has black hair, olive green eyes, and a relatively pale complexion.
Ryosuke is a very perverted boy who often finds himself at odds with girls due to his outrageous comments (many of which he accidentally mumbles while thinking to himself). However, his erotic thinking is actually what drives him to being a person who truly cares about the well-being of all girls. He considers them as "treasures" and vows to protect all girls.
Charge up his energy by getting aroused (It seems that there is more energy when he is aroused from Lisara)
- He is voiced by Hiro Shimono