Itadaki Kazuya

Itadaki Kazuya is a large Deadman in Deadman Wonderland. He is known for eating a lot. His nickname, "Masu" (or "Mass"), is a pun when combined with his given name; the word いただきます (itadakimasu)  is the traditional Japanese expression used when beginning a meal which is the equivalent to saying "let's eat" or "dig in." He has been shown to have a very large appetite, consuming masses of food over a short time.

Background
At some point in the past, Masu became a Deadman and was imprisoned in Deadman Wonderland. Masu's mouth has been split open due to him eating unordinary things.

Appearance
Masu is a very large man, but not very tall (about Ganta's height). He has black hair that he wears in a topknot. He has a round head and his mouth is ripped open through the sides, but it is stitched. He wears a dark blue overall over the standard prison uniform. The bottom part of the overall ends at his knees. At the height of his stomach, there is a zipper on his overall.

Personality
Masu is most known for his large appetite. He will eat anything that can fill up his stomach. It also seems that he is never satisfied and always wants more. If someone refuses him something he wants to eat, Masu will try everything to eat that thing in the end. He also says that he will go on a diet, but postpones it every time. This shows that he is aware of his abnormal appetite but doesn't have a strong resolve to do anything about it. He also does not seem concerned with the nature of the food he is eating as he has been shown eating plates, metal bars and other items most people would find impossible to consume.

He is also used to Deadman Wonderland's insanity, as he was unmoved by Senji's penalty game.

Deadman Arc
Masu first appears accompanying Chaplin, Minatsuki and Idaki Hitara to welcome Ganta into G Ward. Chaplin introduces him as an "ugly fatso". At the welcome party, Masu continues his eating habit and bites a large piece of a robot who came to deliver food. Chaplin then turns on the TV and Senji's penalty game comes up. Just like the others (excluding Ganta of course), Masu doesn't seem phased at all by the horror of the operation and continues eating.

The day after the party, Masu was roaming the corridors of G Ward and encountered Minatsuki. He approached her and tried to eat her flowers. But then Ganta intervenes and offers him his breakfast, Masu gladly accepts this and Minatsuki and Ganta run away. After Masu ate Ganta's breakfast (including the plate and cutlery), he still complains about being hungry.

Forgeries Arc
When Chaplin helps Shiro make food for Ganta, she fails and they have Masu taste test the food. The food knocks MAsu out much to their surprise.

Return to Deadman Wonderland Arc
After Deadman Wonderland was closed, Masu had a retrial. He was sent to a normal prison together with Chaplin. He is seen there eating his cell walls and his urinal.

Abilities
Gluttony: Not to mention his lust for food, but more importantly, his ability to swallow everything he eats and his incredible bite force. He is powerful enough to bite through steel.

Branch of Sin: As a Deadman, Itadaki has the ability to freely control his blood outside of his body.

His personalized Branch of Sin was never shown.

Trivia

 * One of the reasons for his strange sense that anything can be eaten, would most likely be because he suffers from the symptoms of Pica.
 * Only one food item in the entire manga could make Masu sick, and that is Shiro's terrible home cooking.
 * Not much is known regarding Masu's past. There is a chapter banner in the manga where Masu is shown wearing a clown costume before his imprisonment. This suggests an occupation in that area of work for Masu.