We have a flashback about Hinawa, Obi, and Maki before they were in the Fire Force. Hinawa’s flashback shows him freezing up when his roommate transformed into an inferno in the Armed Forces. Obi was a regular Fire Fighter, they weren’t taken seriously by members of the Fire Force.
“I refuse to sit back and do nothing while the world burns down around me.’ – Obi
After finding out that the Fire Force members had a point system to have fun while putting infernos to rest. One inferno waited patiently for the fire force to put in to rest. This is the first time Obi and Hinawa worked together. Obi vows after that moment to create his own sector of the Fire Force.
The Mightiest Hikeshi
Back in the present, the 8th want to investigate the Evangelist in the 7th. They do not want to cooperate, but Obi barges in and makes their presence known. The captain, Benimaru and Shinra have a battle of words because Benimaru isn’t interested in tracking down the Evangelist.
Shinra challenges him to a duel, but one of the townspeople turns into an inferno. While putting him to rest, Benimaru tears his village apart. An old lady explains to Shinra that the townspeople only want to be put to rest by Benimaru’s hands if they combust.
I think Benimaru will become a trustworthy ally once Shinra breaks his shell.