[Crossover] A Superfan, but the Upper Rank Two

Tong Nan, the twin younger brother of Upper Rank Two, Tong Mo

As the only person who could understand and comfort him in childhood, Tong Mo was the one person Tong Nan could connect with. Tong Nan, who should have been incapable of emotion, developed a sick, almost fanatical love for his older brother. He couldn't understand it, but this unfamiliar feeling was deeply addictive.

His older brother, Tong Mo, was also emotionless. But from childhood, he had been exceptionally perceptive about other people's feelings, so he had always known of his younger twin's obsession with him.

But so what? Tong Mo thought.

He, too, loved his younger brother madly.

One day, after willingly turning himself into a demon, Tong Nan and his brother were out hunting when they stumbled upon a pair of siblings. They hit it off and turned the two into demons. Afterward, Tong Nan, the demon of a hundred poisons, unexpectedly gained the ability to see glimpses of the future: a future in which his brother died, and one in which Tong Nan himself did not exist.

So Tong Nan ran away with his older brother.

Muzan Kibutsuji: ??? Where are my subordinates? Where are my two incredibly powerful subordinates who talk back all the time?

Warnings:

* One-sided crushes, but as everyone knows, Upper Rank Two has no feelings, except for his older brother.

* The worlds in this crossover are a bit of a jumble, so I've given up on keeping to a timeline.

* I've forgotten parts of some manga I read a while ago, so please point out anything that's wrong.

* My writing is really bad, waaah.

Theme: Big Brother is the best! (Starry-eyed)