In episode 5 of Fire Force, we find out that Princess Hibana knows the secret to spontaneous human combustion. Of course, she won’t share. She and the rest of her Special Force 5 members have a perverted way of doing research. We find that out during her examination of the abnormal inferno, Miyamoto.
The Battle Begins
If you recall, the last episode of Fire Force (The Hero and the Princess), Obi agrees to let Hibana research the reason for Miyamoto’s consciousness in his inferno state in exchange for her sharing her findings. However, Hibana is not sharing and that forces Obi and the rest of his unit to storm Special Unit 5 to get the information.
Shinra also wants to fight them because they jumped him in the last episode. Iris (the nun in special unit 8) goes to visit Hibana first.
Spoiler alert, that is her sister. However, she has turned away from the convent and is now taking part in perversion.
Based on the end credit scene, something happened at their convent and it must have caused Hibana to lose faith while her sister, Iris kept hers.
During Iris’ visit to see Hibana she fails to sway her back to the light and a battle commences between special unit 5 and special unit 8. Hibana thinks she’s lured special unit 8 to her, but they were already coming.
By the end of the episode, Arthur ends up beating Miyamoto who has become a pet for special unity 5. Maki and Hinawa take out the 3 angels of the 5th. Shinra heads to confront Hibana and Obi is en route.