Ganta Igarashi & Senji Kiyomasa vs Hagire Rinichirō, Chan & En

Ganta Igarashi & Senji Kiyomasa vs Hagire Rinichirō, Chan & En was one of the main fights in Operation Mother-Gizmo Reinforcement.

Prologue
Hagire takes Ganta hostage in exchange for sparing Senji's life. Once they arrive at his lab, Hagire explains his goal to release Wretched Egg's full power by deactivating the Mother Goose System, but in order to achieve this, he requires Ganta's unique Branch of Sin that he cannot copy and proceeds to take over the boy's body with his machine and with assistance from Chan and En's special Branch of Sin. While the process unfolds, both of them can access each other's memories. Ganta sees Shiro's past and her unending suffering caused by his mother and Hagire's constant experimentation on her, which ultimately led to the by-product, later to be known as Branch of Sin and her second personality. Before the process can be completed, in the nick of time, Senji bursts through the door, severing the connection between the two and proceeds to rescue Ganta.

Battle
Hagire orders Chan and En to stop Senji's interference. They attempt to shoot him but get easily pushed back with a mere punch. He approaches the glass chamber and attempts to free the barely conscious Ganta when Hagire ambushes Senji from behind and entangles him in a blood net, stating that he will be reborn as Ganta. He then reuses the same barrage of attacks from his previous battle. Despite suffering numerous blows, Senji manages to overpower him. While Hagire tries to evade his attacks, Senji tricks him by extending his Crow Claw and breaks the container holding Ganta. He tells the boy to run while fending off Hagire's attacks. As Ganta is unwilling to leave, Senji kicks him back and asks him for this one chance to be prodigious. As he leaves, the twins attempt to follow him, but Senji blocks the path with his Crow Claw barrier leaving them to battle alone.