Oboro is a humanoid black cat who resembles a middle school student. His eyes are red, and has medium black hair and cat ears, which come down over the side of his head to form a "chullo". He is extremely slender, and has long arms and cat feet. He wears a red vest along with "pants" that come up to his waist secured by a belt.
Oboro has the average personality of an adolescent in middle-school. He is overconfident, eager to fight, and dislikes working for people older than him. When it comes to Ageha, he will only do the bare minimum to serve her due to her lack of appreciation and disrespect for him. He cares little for material things and money due to his high salary and luxurious lifestyle from living with Ageha. He is also observant enough to know when he is at a disadvantage and when to ask for help. For example, when both he and Rokumon were taking an exam to raise their ranks, they both worked together during a free-for-all fighting test because they needed each other's help.
Oboro comes from a family that served Ageha's family as Black Cat Contractors for generations, and he is continuing that tradition much to his own chagrin.
He and Ageha grew up together, but they tended to fight each other, for she played roughly with him and he would hurt her then. When she tried practicing for the future, Ageha got hurt by a mother hen of an evil chick hatching, and while it looked like Oboro abandoned her, Ageha told the adults that she was by herself when she got hurt. She made it clear to Oboro that she would be the one to have him as her black cat by contract and that she wouldn't have him form a contract with anyone else.
A year ago, she finally made her contract with Oboro, and when they went on their first mission together to capture an anaconda spirit, Oboro captured it himself and he teased and taunted her with it, causing Ageha to throw an exploding skull at him, burying him under rubble. And Ageha did not realize he no longer came to work because he was stuck.
Oboro finally got out, and set out for revenge against Ageha using snake spirits. As she reminds him that he can't go against her as long as she has their contract, a fight occurs between them, as Oboro tries to destroy the contract, but when Ageha fires him when she gets a chance to be alone with Rinne, Oboro gets mad for having been fired for such a stupid reason, prompting her to ask him if he really hates her that much, and Rinne reminds them of how a relationship between a Shinigami and a Black Cat is built on trust, so they sort of reconcile.
Ageha nagged him to take the Black Cat Contractor Ranking Exam, and he succeeded in the cooperation test, but was hilariously overwhelmed by Suzu in the other 3 tests. As a result, he got an unconditional pass.
When the Black Cat Secret Meeting took place with no knowledge of its purpose, Oboro assumed it is a protest rally against the Shinigamis and led the Black Cats in a poorly planned revolt against their Shinigami partners until the real purpose of this meeting is discovered, and collapses in disgust like everybody else when the winning prize is revealed.
In the final story, he, Suzu and Kuroboshi III searched for a lion headed faucet that pours water from the Sanzu river which is dangerous as it would send anybody with a boundary stone directly to the Wheel of Reincarnation, and they failed to notice that it was right behind them stuck in a fountain when they met upon Rokumon who finds it. The 4 are last seen enjoying a picnic together.
Even though Ageha and Oboro grew-up together, neither of them can stand each other, especially since Ageha ignorantly treated him poorly as a child, which sparked his long standing grudge against her. Even now, they would keep on fighting each other.
Orobo and Rokumon are on good terms. Whenever they meet they are friendly and speak to each other respectively. When they were both taking an exam to increase their ranks, they were both willing to help each other during a free-for-all test with no distrust, defeating many other black cats as a result.
- "For such a stupid reason, you'd fire me?" (そんなくだらねー事のためにおれをクビにしようとしていたのか！) - Chapter 90, upon realizing Ageha left him his contract to not have him interfere in her plan to be alone with Rinne
- "Why can't you be honest and tell me not to quit?" (なんて素直に辞めないでくれないと言えねえんだ！) - Chapter 90
- "Yeah, because I'm the only one who can deal with such a selfish Shinigami" (ま、こんなワガママな死神とつき合えるのはおれぐらいなもんだからな) – Chapter 90, responding to Rinne why said he should not quit
- Orobo's salary is ¥500,000, which is equivalent to $5000. According to Rokumon and Rinne, this is quite high compared to the average black cat salary.