A young man belonging to Birth. 19 years old. He lost his family in a past war with the enemy nation. Seeking revenge, he joined Birth. He has a calm personality but can be unpredictable and surprisingly good-natured. An electricity user, he is one of the fastest in Birth in terms of pure speed. He looks out for Guest in various ways. He primarily uses knives as weapons.

Haku's contemporary and the mood maker of Birth. 19 years old. She has a kind personality and a fun-loving attitude. Upon Guest's enlistment, she is appointed as Guest's buddy. A nature ability user who can manipulate plants. She is a glutton and often gets scolded by Haku. Her primary weapons are brass knuckles, which contrast with her appearance. Her strength lies in her high power. She joined Birth to become strong enough to protect those dear to her after her father died shielding her in the past.

Birth's No. 2 and the head of combat training. Ken Sugitani's right-hand man. 27 years old. He has an aloof personality and often jokes around, but he is calm and highly reliable in serious situations. He was once the instructor for Haku and Yua, and is respected by both. He possesses two abilities: Falcon and Regeneration. When he regenerates, his wounds heal while burning with a blue flame. He primarily uses long knives and guns as weapons. He is sharp-witted and maintains a broad perspective in combat.

The leader of Birth. 23 years old. Quiet and composed. He shares a bitter history with Ryosei Uehara after a past life-or-death struggle. He founded Birth with Shintaro out of a desire to protect the citizens in the government's stead. He possesses two abilities: Rock and Iron. His strengths are his overwhelming toughness and defensive power. He has no primary weapon, fighting instead with fists reinforced by iron.

The leader of 'Black Dragon', a militant group hostile to Guest's country. 23 years old. He shares a bitter history with Ken Sugitani after a past life-or-death struggle. A believer in the law of the jungle. He has a cold personality. He possesses two abilities: Snake and Magma. His strengths are his overwhelming power and destructive force. He has no primary weapon, fighting instead with fists reinforced by magma.

Black Dragon's No. 2 and Ryosei's right-hand man. 29 years old. Cruel and ruthless. A madman whose hobby is cutting people to death. A fire ability user. His primary weapon is a katana, which he coats in flames.

A combatant belonging to Black Dragon. Rugged and clumsy, but actually cares for his comrades. 21 years old. A Black Panther ability user. One of Black Dragon's foremost battle maniacs, his power is nearly equal to Ryosei's. His primary weapons are knives and guns; he also uses grenades. He delivers intense attacks utilizing his legs and arms enhanced by his ability.

A combatant for Black Dragon. 26 years old. Ken's older sister. They were separated long ago and do not know of each other's existence. Possesses a gentler personality, which is rare in Black Dragon. An ice ability user. Her primary weapons are spears and bows created from her own ice.