Senzai Uchiumi .

Senzai appears as a slim, pale man with prominent eye bags, and a tired expression on his face. He is seen wearing a tight black shirt

Senzai appears as a slim, pale man wearing a sleeveless kimono. He wears black pants and a black dress that parts in the middle. His finger nails and toe nails are painted black, and he wears long black strips of cloth around each of his arms that curl outwards at the ends. He has black curly hair that falls to his shoulders and a crazed expression across his face. He has an abnormally large grin revealing a large set of teeth and black snaking scars across his head. He has large hollow eye sockets with small yellow pupils inside of them.

Senzai remains like chapter 3’s form but with his hair down. His blindfold is now removed, revealing his glowing yellow eyes and a scar on his forehead

Senzai is the eldest child of the Uchiumi Family and used to be the favourite child because he was the first born and has great academic skills that his brother, Isamu didn't have. However, after his father discovered that Senzai disliked the idea of being forced to work in the law field as a full time career and that he wanted to go to an art university (which he got accepted to), he became the least favourite child.

His mother passed on and he now lives in the minka with his father and younger brother, Isamu. His father has disapproved of anything Senzai has done since the art university letter problem.

Senzai grew to despise Isamu and always considered him a 'liar'. When they are adults, Senzai sails out to the sea and meets Kyogi, who appears to be explaining something to him. It is then shown that Kyogi and Shosai throw Senzai's decoy (mimicked with black goo) into the sea[4], leaving Senzai in the back, enraged, and thus, becomes The Worshipper.

Sometime later, "Senzai" was mysteriously found dead on Aogashima Island. Isamu, who is a pathologist, was assigned to do his autopsy. Senzai's "body" lies lifeless in the autopsy room of the office with only mysterious black substance found in his body. This mysterious death led Isamu to investigate the scene himself in Aogashima Island.
After Isamu's boat was capsized by the Umibozu, he managed to get a glimpse of someone dragging his body ashore before blacking out again. We found out that this someone is, in fact, Senzai as The Worshipper. Later on, an illusion of The Worshipperappeared to jumpscare Isamu as he enters Yoki Town, where he last appear in this chapter.
Isamu wake up to find The Worshipper calling out to him. Just as he was running towards him, he awoke from what is apparently just a vision.
After the defeat of Nagisa and her reincarnation, The Worshipper ambushed Isamu from the back and blacked him out. After Isamu awoke, he found himself in someplace underwater with The Worshipper in front of him, who then reveals himself as Senzai. He then ridiculed Isamu for trying to "avenge" him, and explained to him his revelation and purpose. Senzai then greeted his God who rules his current world, Enzukai, to Isamu.

Enzukai mentions Senzai during its confrontation with Isamu at the Twisted Lake, exclaiming how Senzai is gone and that it was the only one there for him. After the confrontation, Isamu arrived at Senzai's memory in The Father's Minka, and saw him standing in front of it as The Worshipper, before he disappeared upon being approached. Isamu saw Senzai's memory of him doing house chores for three nights, but then getting abused by their father for 'not behaving'. In Senzai's memory, he viewed Isamu and Akihito as monsters, a twisted manipulation by Enzukai to trick Senzai, originally.
Senzai was absence throughout the whole chapter after that, until he was seen at the end credits card along with Enzukai's second form and the other Kiiroibara Cult memberswreaking havoc in Tokyo.
Senzai appears momentarily throughout the destroyed office, taunting Isamu as he's finding the numbers to the storage room code on each floor. If Isamu stare back at Senzai, he'll continue to choke him, and Isamu must free himself.
Senzai appears again later on in the temple, personally hunting down Isamu alongside the rampaging Kutsu. If Senzai sees Isamu hiding in a cabinet, he'll pull Isamu out and continues to choke him. When Isamu frees himself, he'll go on to throw a punch to Senzai's face, temporarily stunning him with enough time for Isamu to lose him. After Isamu crafts the blessed bow, Senzai will no longer chase Isamu in the temple, and only appear in the entrance gate after Isamu leaves, stating that he'll never understand the pain Senzai has went through.
At the final fight, Senzai will occasionally teleport into the battlefield to halt Isamu's attacks on Enzukai-Ryujin. Upon shooting two arrows at him, he retreats temporarily.

Before the final blow to Enzukai-Ryujin, Senzai will desperately tell Isamu to stop killing his God, and to instead kill him, stating that it's what their Father would have wanted.
Upon shooting the final arrow at Enzukai-Ryujin, the curse on all Kiiroibara Cult members would be lifted, including Senzai's, turning him back to his human form. He cowers knowing that he has no one else to run to. However, Isamu extended his hand to Senzai,despite everything he's done. Before their hands meet, the time Shihyosha gave to Isamuwas over, and his body drops lifeless on the ground. Senzai only managed to express his apology on Isamu's grave with regret. As a form of self-punishment, he decided to turn himself in behind bars and pay for what he's done in every way he can until the day he die.

Canonically: 24
Chronological: 28 years old (as of 2025)

Human
Monster (formerly)

Languages:
Japanese
English (presumably)

Country:
Japan

Nationality:
Japanese

Religion:
Kiiroibara Cult(formerly)

As a human, he seemed to be a soft child, one that people would describe to be good. He would do everything to satisfy his father, without complaining one word.

However, he is shown to be capable of harboring vengeful feelings from the way that he resented Isamu for becoming their father's new favorite child. Easily blinded by these bitter feelings, he grew to become a rather close-minded and pessimistic person, as can be seen when he accuses his brother of not caring about him