Tesshin "The Fatal Hand" Kushiya is a member of the Shishigami and Inaho's foster father. He is strong enough to fight maken users barehanded. He doesn't use a maken and his power and ability is equal to Ouken. He also the one that supposedly "murdered" Takeru's mother Atsuma 10 years before the storyline began.
Tesshin is a giant man, towering over everyone he encounters, with spiky hair that points backwards. The scar on his face was the result of his fight with Atsuma.
He has tiny pupils, therefore giving the impression that his eyes are pure white.
Tesshin Kushiya was a stray ability user. One day he found Inaho abandoned on his door step. Tesshin took her in as his adopted daughter. He gave her the name "Inaho", and sometime later he began to train her, as that was the only thing he knew to teach. Ten years before the start of the main storyline, he takes Inaho with him down to the city to visit a friend. Tesshin begins to feel he might lose his daughter so he becomes more strict with her and increases her training; however, Kamigara imprisoned him for kidnapping and child abuse. Ouken later frees him on the condition that he fights Ouken's rival, Atsuma. After defeating her, Tesshin leaves Inaho in her family's care in order to do more training, feeling that his own soul was defeated in that fight. However, Atsuma makes him promise to return for Inaho, which he claims he will do when he feels he is as strong as Atsuma.
At some point he finds a cave on an island and uses it as his meditation place.
When Takeru finds his cave he questions him on his reason for coming. When Takeru attempts to attack him, he makes a fist and punches Takeru away with his fist's air pressure. When Takeru screams that Tesshin killed his mother, he deduces that Takeru is Atsuma's child, but is confused at the accusation that he killed her, since she was already dying when they fought. However, he accepts it, and claims he and Takeru are sworn enemies, and calls for a fight. He and Takeru begin to fight, although Tesshin fights with his eyes closed. Tesshin, noting Takeru's good instincts, begins to command him about how to fight while they do so. However, as Takeru's fear begins to overwhelm him, he becomes disappointed, and tells him to leave. After Takeru's epiphany about his own faults, he rushes Tesshin, who gets excited as Takeru's eyes are now just like Atsuma's. He mentally asks Atsuma for forgiveness, claiming he was foolishly chasing her strength, as he punches Takeru. He is shocked that Takeru broke his own back to avoid the punch, and more so when Takeru bites him and uses Tesshin's Element to heal himself. After Takeru lands a massive punch, Tesshin realises that Takeru is using Blood Pointer, and tells him about Blood Pointer's ability to take people's emotions, good and bad, and turn them into Element. He thanks Takeru for showing him how to use Blood Pointer, while Takeru tells him that Tesshin has also helped him to understand something. Tesshin is overjoyed that the last 10 years of training he thought were for nothing now have a purpose. He later puts Takeru on his back (after Takeru loses) and starts to climb out the cave. He reveals that Inaho is his daughter, much to Takeru's shock, and tells him his back story, claiming he didn't deserve to be called a parent.
When they climb out of the cave, Tesshin sits by Minori until she awakens, but stops her from going after Ouken, telling her that Takeru will fight him and that he believes Takeru will come back alive. He tells her the reason Takeru can now use Blood Pointer, and tells her she is blessed to have a student that thinks the same way she does. As he believes no one beat Ouken as he is, he offers Takeru his Element. When Takeru mentioned he will repay the debt, Tesshin asks for him to bring a sweet snack.
Tesshin is a powerful fighter, as evidenced by him defeating Atsuma Ooyama. Hakuto has stated that his ability is equal to Ouken's/the only ability capable of challenging Ouken's. Tesshin has shown that his fists have enough pressure to push people away with a punch. Tesshin says that his own blood pointer ability is an imitation of the blood pointer, this consist of absorbing the breathing of other living creatures around him. However, he considers it an imitation to the ability he sees in Atsuma, and consequently Takeru.
He is strong enough to defeat S-class maken users without having a maken himself.