Chuya Nakahara "Is the Universe Infinite?".au.

Osamu now found himself in a world without abilities, mafia, or agency. He understood that this was his last chance, and each time he tried, he went a little madder.

Once, in another universe, as a detective, he found an esper with the ability to travel between universes. Osamu chased the universe where he and Chuuya were together. His love for him was insane. They were a detective and a mafia member. Bad luck, Chuuya hates him. They both ended up in the mafia, but it didn't work out again. In another universe, Chuuya wanted to kill him outright. In another, he's homophobic, and Dazai was going crazy. However, he was stuck in the last universe. Here, there were no abilities, no mafia, no agency, no violence, no death... They were just there, sixteen, and everything seemed fine. Chuuya was still the same: hot-tempered, abrupt, small. Every night, the brunette couldn't stop thinking about this redhead; every time, the only thing that kept repeating in his head was "Chuuya, Chuuya, Chuuya." Osamu, without even noticing, bit the fabric of his pillow, feeling a hot tug every time.

One such night, Osamu received a notification on his phone from a contact named "Chuu." Osamu immediately responded to the ginger boy's message.

— "Are you sleeping?" Dazai read this short message and his heart skipped a beat. — "No, did you want something?" the brunette replied instantly, and the next message made all his excitement evaporate, "I think I'm in love." Dazai's heart sank. — "Yeah? With whom?" Osamu typed with trembling hands, and the answer completely killed him. "Yosano." Dazai hated their mutual friend. Why her? What was he doing wrong? Was it really happening again?

They agreed to talk at school, but Osamu couldn't sleep. His life had been turned upside down by jealousy and loneliness.

The next day, Dazai overslept and rushed in, meeting the redhead waiting at the gate. "Idiot, overslept again!?" the redhead grumbled, looking at his friend with displeasure.

"Don't be angry, Chuuya. I got a little carried away reading before bed!" Osamu replied nonchalantly, though pain and melancholy were churning inside.

"Let's go already, idiot!" the red-haired man growled at him.