Koyū Azuma

Koyū Azuma has mechanical arms and legs made with special technology from the Shinoyama family. After an accident, his right arm was replaced again with a dragon’s arm, which looks very powerful and unique.

Koyū is very loyal and sincere, taking his job seriously and completing all tasks, even simple ones like buying shark-themed gifts for Saya Shinoyama.

He cares about details and is a very skilled cook, showing both discipline and passion.

However, when it comes to fighting or dealing with enemies, he can be cold and ruthless.

He also has a sense of jealousy, especially toward Polka Shinoyama because he shares blood with Rozan.

Koyū was born into the "Black Thunder" assassin family.

When he was nine, his first mission went wrong after meeting Majiri Agakura.

She asked him to join her family and took away his arms and legs, leaving him unable to work as an assassin.

His own father planned to use him as a living "garden pot" for growing poison, but Rozan Shinoyama rescued him before that happened.

Since then, Koyū feels a deep loyalty and love for Rozan, much more than for his real father.

He is now cut off from his family, except for his elder sister, Enmei Rai, who loves him very much and often sends him extremely long messages.

Koyū uses weapons like kunai and takes full advantage of his mechanical arms and legs.

He can stretch his fingers for wide attacks, give electric shocks, and jump very far and high.

His hearing is so good that he can hear other people’s heartbeats.

Later, after his right mechanical arm was destroyed by Majiri Agakura, he received Urdwigia’s dragon arm from Corpse God, allowing him to use lightning magic and move at the speed of lightning.

• Rozan Shinoyama: Koyū respects Rozan deeply and is very loyal to him, since Rozan saved him from a terrible fate.
• Polka Shinoyama: At first, he was jealous of Polka's close tie with Rozan, but they later became allies and understood each other.
• Corpse God: He was cautious of Corpse God at first, but later agreed to form a team after discussions and advice from Rozan.
• Saya Shinoyama: As her bodyguard, Koyū admires Saya’s calmness and thinks she is impressive because she didn’t panic after discovering his true identity.
• Majiri Agakura: She is the one who caused Koyū to lose his arms and legs during his first mission, and asked him to join her.
• Enmei Rai: She is Koyū’s elder sister and loves him extremely much, often sending him very long, passionate messages.

Childhood Tragedy and Salvation

Koyū Azuma lost all four of his limbs during his first mission at just nine years old after an encounter with Majiri Agakura.

His father wanted to use him as a “garden pot” to grow poison, thinking Koyū was useless as an assassin.

Rozan Shinoyama intervened and rescued Koyū, giving him mechanical arms and legs.

Life as Rozan’s Loyal Protector

After being saved, Koyū devoted himself to protecting Rozan, viewing him as a true father.

He moved into Rozan’s building, acting as Saya Shinoyama’s bodyguard.

At first, he was suspicious toward Polka Shinoyama, but after many events and learning about different worlds, he started to trust Polka and work together with him.

Encounter with Majiri and New Powers

Koyū later met Majiri Agakura again, who broke his right mechanical arm.

Corpse God replaced the lost arm with the arm of the thunder dragon Urdwigia.

This special arm granted Koyū the power to control electricity, wrap himself in lightning, and move at amazing speed.

Koyū is highly skilled in cooking and cares about the quality of his food.

Even basic requests, like buying shark merchandise for Saya, are important to him and he completes them carefully.

He is separated from his family, but still keeps in touch with his sister Enmei, who loves him more than words can say.