Masato (魔狭人) is a wealthy demon from Hell and a recurring antagonist in Kyoukai no Rin-ne.
His short hair and eyes are dark purple, and has bat markings on his cheeks and bat wings. He is mainly wearing a Tuxedo.
Masato is rather cruel, showing no pity for even women and children. He is underhanded in his attempts to seek revenge against Rinne, and often resorts to using his vast fortune to gain the upper hand, though he sometimes shoplifts and use a bomb to cause a distraction, which got the animosity of many such as Kain and Renge. His intelligence seems to be slightly lacking, as he often miswrites kanji, and his traps are often childish and easily backfire on him.
Six years ago, during his time at Demon Elementary School, he was given a homework assignment to retrieve an irreparable soul and bring it to hell. Masato found a rabbit that had been kept in a hutch behind a school in the human world, that was soon going to die from loneliness. Just as he was about to take the still living rabbit's soul, Rinne arrived, telling him that the rabbit was not yet ready to pass on, and fed the rabbit, causing its spirit to return, and thwarting Masato's completion of his homework assignment. Enraged, Masato attempted to attack Rinne with a pitchfork, but Rinne smashed him over the head with a large crucifix (scythe in the anime), thus beginning their long-running rivalry.
Masato prepared revenge against Rinne, using a spirit as hostage to lure him to Hell and throw him to the absolute lowest level of Hell called debt hell, rendering him unable to ever leave Hell. He found the spirit of a Sankai High student named Todoroki Reiji, who left his body to find something he lost after stumbling against a street phone pole three days ago, and corrupted his soul to turn him into an evil spirit bent on attacking his girlfriend Minami Suzu and best friend Tadano Tomoya under the delusion that they started dating since he got in the hospital, until he’d be able to take his soul to hell, forcing Rinne to follow him. As part of Masato’s conspiracy, on top of being an illegal intruder, Rinne caused massive damages during the chase, which would cause the repair costs to be billed to him, and Sakura and Rokumon used a credit card which gave many bills that are actually counterfeited and brought them to Rinne. But Rinne used those bills in a different unexpected way against him, and by forcing Masato to cover for Rinne’s intrusion and damages in exchange for not revealing to the authorities that he printed the fake bills, Rinne was able to leave Hell with Sakura, Rokumon, and Reiji’s spirit, which returned to his body.
He would keep trying to bring disaster to Rinne in many different ways, only for Rinne to turn the tables and hit him in the head.
Once, as part of his business, he left envelopes containing demon-summoning amulets in the cottages of a campsite, to corrupt souls and take them to hell. A young boy Toichi was tempted, but as his sister Kana got worried about him, Sakura came along with Rinne and Tsubasa, which caused Masato to use the demon-summoning emblem to summon an army of 1000 demons, only for the legion to be away on vacation.
Another silly prank on Rinne led him to bump into new Sankai High Teacher Annette and he took interest in her Scrying Orb, cursing it causing the image of the future to be tampered, guiding the person in the wrong direction. A fight between a demon and a witch ensued then, as Annette used a seal to preclude him from leaving her house, and he thus summoned a Cerberus, who would vomit and urinate creepy animals (snakes, frogs, scorpions, spiders…) over the house, but Rinne knocks them both out, and Annette manages to clean her orb.
He would be bestowed angel wings by an angel, for allowing her to eat steamed bun by throwing away trash at a cursed swamp of hell, which was painful for him as it caused him to help people instead of bringing disaster. But Rinne helped him recover his devil wings, although it was in hope of getting malignant eradication points for the evil spirit exorcism reinforcement Weekend.
He haphazardly gets acquainted with Rinne’s family, when he pickpockets a credit card from Tamako, and uses it to buy a Medusa Mask stolen and sold by Sabato, who schemed to make an illegal copy of the credit card. Masato tried using the mask to turn Rinne into stone, and Sabato would endure their fight to keep selling them accessories, but Rinne stopped them both.
Flight: Masato can fly through the use of his wings. When disguised as a human, he can make his wings disappear. Should his wings be stolen, he can no longer fly.
Devil's Fire (デビルズファイヤー): Masato can make a fireball appear. Once it is blasted towards the target, one can see flaming bats within the ball.
Devil Cash Card Cut (デビルキャッシュカードカット): This attack involved throwing many (fake) ATM cards at the target. This attack, while not magical, is strong enough to return Rokumon from his demon cat form to his original form.
Hellfire (地獄の業火): This attack is just a stream of fire from Masato's hand.
Resentment is all Masato fells over Rinne, and making Rinne suffer is what he thinks mostly.
Feeling disgraced to have been manipulated by a demon, Tsubasa resents Masato ever since.
Annette resents Masato, ever since he cursed her orb.
- “I haven’t for one day forgotten my hatred over you, Rinne.” (僕は一日たりともキミへの怨みを忘れたことはないよ、りんねくん) – Chapter 14, when he meets Rinne again after 6 years
- “When it comes to being narrow-minded, I can’t lose to anyone.” (心の狭さなら誰にも負けない) – Chapter 14, after presenting himself
- “What a ridiculous accusation” (とんだ言いがかりだな) - Chapter 50 and 72
- “Stop with the false accusations, Rinne” (言いがかりはやめてくれ りんねくん) - Chapter 158 and 298
- “Though it would be good if you die” (死ねばいいのに) - Chapter 158, while eating Barbecue with Rinne and Rokumon
- “Damn, for me to lose to the likes of a witch…” (くっ、この僕が魔女ごときに。。。) - Chapter 231, while Annette cleans her Scrying Orb
- “I see… When I couldn’t help getting irritated at the sight of that red haired old man’s face… It was because you are father and son! It didn’t even cross my mind” (そうか。。。その赤い髪のおっさんの顔、どうしようもなくイライラすると思ったら。。。親子だったとはな！考えもしなかったよ！！) - Chapter 298, upon learning that Sabato who’s been selling him equipment is Rinne’s father
- His name means narrow-minded person and he seems to be proud of it. It could be because he doesn't know the meaning.
- The bat markings on his cheeks are reminiscent of the dog demon marks of Sesshōmaru from Inuyasha. He otherwise bears a heavy resemblence to Ranma 1/2 character Pantyhose Taro.
- The back of a cash card he owned had a pin number on it, which was "4-4-4-4". The number four is an extremely unlucky number in Chinese, Japanese, and Korean culture and is correlated with death.
- Compared to the other demons in Hell, Masato is much more vampiric and Western in appearance while the other demons look more like traditional Japanese "Oni".