No Vaccine Needed, Just Bite People and Go Mad

[Infinite-worlds, male protagonist pursued by other men + both reborn + devoted to each other + apocalypse + rules-based horror + instances + guilds + sweet and angsty romance]

A thin-skinned, sharp-tongued uke × a steady seme with a doting, fatherly streak

The apocalypse came, they were reborn, and he went from being useless to becoming a joke.

Zhao Xinlang mistakes a villain for his benefactor. As he suffers both physical and emotional torment, he is also mocked by You Zhunan, the man who killed him in his previous life. He can do nothing but swallow his anger, and he can't even kill You Zhunan.

Just one taunt from Zhao Xinlang changes You Zhunan's life. You Zhunan stops thinking about Zhao Xinlang's current predicament and starts thinking about his naughty bits instead.

You Zhunan had never felt that way about Zhao Xinlang, whom he regarded as his little brother. But he realizes Zhao Xinlang is no longer the “little wolf” who left him, and falls in love with him.

Zhao Xinlang regains his memories but doesn't dare tell anyone, because all he wants is to be Zhao Xinlang.

You Zhunan is willing to lay down his life for Zhao Xinlang. Their contract from two lifetimes ago becomes his best excuse. “If you die, I'll die too.”

Anyone else would think this was a curse, but he just happens to need a whole lifetime to atone for his sins.

P.S. The angst and sweetness are both off the charts. Read with caution. If that's not your thing, stay away.