Oboro (朧 Oboro?) is the father of Aya and Saki. He first appeared in THE OneeChanbara, although he was unnamed at the time. He is reimagined in OneeChanbara ORIGIN.

In OneeChanbara ORIGIN, Oboro is a master swordsman and a member of the cursed Baneful Bloodline. He is on a journey to avenge his wife Tsubaki by finding and killing her murderer.

Oboro and Tsubaki were an assassin duo who constantly fought against nefarious parties such as Uroboros who wished to use their Baneful blood for unethical research. Oboro was a sword master while Tsubaki was a martial artist adept at a style she called Mortal Combat. One day, Tsubaki injured her leg, forcing her to retire early and Oboro to make ends meet by himself as a lone assassin. As husband and wife, they eventually bore Aya and then a few years later Saki.

As members of the Baneful Bloodline, Oboro and Tsubaki's family was subject to a fatal tradition in which they were supposed to train their daughters to fight each other to the death, the victor carrying on her bloodline. To protect their daughters from this Baneful tradition, they pretended that Aya and Saki were not full sisters, telling Aya the lie that her real mother died right after she was born. Soon afterwards, the family split up, with Tsubaki leaving with Saki and Oboro staying with Aya.

Oboro trained Aya everyday in the ways of the sword until she became his equal several years later. One day, however, Oboro caught word that Tsubaki had been murdered, enraging him and causing his Baneful blood to go Berserk. Not in the right mind, he invited Aya to another training session with the intention to kill her. Thankfully, Aya was able to resist Oboro enough for him to temporarily regain his senses. Realizing that he almost killed his daughter, Oboro leaves behind Aya to search for his wife's killer.[1]

Two years later, all the while preventing his Baneful blood from completely consuming him, Oboro eventually discovered that it was a Baneful woman named Eva who killed Tsubaki and was also using her heart to brainwash and control Saki. Having originally intended to avenge Tsubaki by saving their daughter and killing Eva, Oboro realized that he was nearing his limit on resisting his Baneful blood. At a hospital's basement near Saki's location, he was ambushed by Uroboros clones. Unfortunately for them, they were no match for Oboro and were slaughtered. His Baneful blood went Berserk soon after.