Chan and En

Chan (チャン) and En (エン) were the adoptive children of Hagire Rinichirō as well as his loyal servants.

Background
Chan and En were born twins. With only half of their mind, they were left in a comatose state during the majority of their childhood. At some point after the Great Tokyo Earthquake, they ended up gaining a Branch of Sin and with it, they hacked into the medical monitors at their hospital and made it known that they were alive. Hagire Rinichirō soon adopted the two.

Appearance
Chan and En both wear the same clothing and look exactly the same (with the exception of their hair). They wear a black formal suit with a white shirt under it. They also have a red tie. En's hair reaches over her shoulders and Chan's is shoulder length. They are albino so they have red eyes and a somewhat grey skin.

Personality
Chan and En care a great deal for Hagire (as seen when they could hardly restrain themselves when Tsunenaga Tamaki went bowling with Hagire's head). They demonstrate a great deal of loyalty and obedience towards him, protecting him from harm and serving him on every command. Despite this, however, the expression on their faces are always blank. They always speak in an almost robotic manner, completely devoid of any emotions, with few exceptions being when they cried in the hospital, showing relief and joy when Hagire gave them a chance in life, enabling them to walk and speak. Before getting killed, they expressed a deep love for Hagire as a father with a smile, despite him being apathetic towards them.

They see children as being ignorant, never realizing that they're always being protected.

They are very submissive, as seen that they served Tamaki a short while after Hagire's second generation died. They are also very strict, as they refused Makina entrance, just because she didn't follow the procedure.

Deadman Arc
They first appeared when Makina sought an audience with Deadman Wonderland's director, Hagire. They refused to let her in and threatened her with their bayonets. She then left angrily.

In the anime, after Shiro (as the Wretched Egg) rampaged at a control post, Chan and En are there to pick her up and take her back to her room. Chan briefly looked at Yō but didn't feel the need to remove or approach him.

Scar Chain Arc
The next time Chan and En appear is after the director "died". Tsunenaga Tamaki saw the director's severed head and was happy that it would finally be his Wonderland. To celebrate his joy, he made Chan and En position bowling pins and Tamaki played bowling with Hagire's head. The twins had to resist the urge to kill him since Tamaki was their superior now. They bottled up their frustration and they were seen pinching their hands so hard that they would start to bleed.

Forgeries Arc
The Twins appear a few times in the Forgeries Arc. They're always seen near deceased Deadmen, collecting parts of them. Shiro runs into them telling them that she's a Deadman now and she'll fight them if they want. The Twins belittle Shiro, calling her an ignorant child.

Revolt Arc
The Twins reappear with Hagire, now in Toto's body, to reveal themselves and assist him in search for the Wretched Egg. They later go to get the Wretched Egg alongside Hagire. The Twins are later present when Hagire confronts Ganta, Tamaki and the Deadman Wonderland Special Hunting Force.

Return to Deadman Wonderland Arc
Later on, when the protagonists return to Deadman Wonderland, Hagire captures Ganta (in exchange for Senji's safety) and prepares to force his memories into him using Chan and En's special Branch of Sin: Hollow Swallow. As Hagire is about to take over Ganta's body, Senji enters and fights briefly with Chan and En while they're using their Branch of Sin: Hollow Swallow Dance Macabre to synchronize their moves. They appear to have the upper hand but are quickly defeated by Senji, who saw past their technique. Senji, thinking he had defeated them, runs off to stop Hagire. When Senji gets ready to kill Hagire, the twins quickly intervene and En pushes him out of the way as they get impaled on Senji's Evolved Crow Claw. They tell Hagire they love him. He declines, saying he never loved them. They smile, claiming they knew all along, as Hagire uses this opportunity to attack Senji, slicing the twins into bits along with half of Senji's right arm.

Equipment
Rifle: Chan and En both carry a black rifle with a bayonet attached to the top. Both have extreme expertise with their rifles, to the fact that they are completely accurate, even when dodging. The rifles were destroyed in Chan and En's battle against Senji.

Abilities
Branch of Sin: Being Deadmen, Chan and En can freely move their blood outside of their bodies.

Branch of Sin: Hollow Swallow: This Branch of Sin allows them to make connections. The connections that they establish with their Branch of Sin allow them to connect mind to machine, or mind to mind. Hagire Rinichirō came across Chan and En when he was in his original body. He met them in a hospital where both were in comas and were widely believed to be almost dead. Rinichirō however, realizes that this is false because their Branch of Sin allowed them to hack into the hospital's computer system and send out a message that they were both alive. Rinichirō thinks of the computer system like a body, and extends Chan and En's Branch of sin to the human population. Hagire Rinichirō uses this ability to overwrite another human being with his memories, lengthening his own life. They perform this by cutting off their right and left hands. Their blood flows out of their limbs, surrounds the subject and they lay their hands on a device connected to Hagire. When this connection is made, Chan and En bleed from their eye closest to Hagire (Chan from his right eye, En from her left eye). The strands of blood cover the subject's eyes and from there on, Hagire's memories begin to overwrite the target's. By the times the memories are overwritten, the target's memories will be annihilated, resulting in their death.

Branch of Sin: Hollow Swallow Dance Macabre: This Branch of Sin is used by Chan and En when fighting. It completely coordinates their movements, so they act like a single fighting machine.

Trivia

 * They are named after Chang and Eng Bunker, the "original Siamese twins."
 * It can also be noted that Chan and En's background could have been inspired by the Siamese twins, as they couldn't function without each other, being fused together from birth.