If anyone's confused, the term Yul used to call Mikhail is "Gwanggong" which means crazy obsessed top, or like a yandere seme. I think it's an internet slang used by Koreans mostly in BL media, that's why Mikhail doesn't know the word. And since there's no direct English translation for Gwanggong so I think that's why translators used "Obsessive Maniac"
If anyone's confused, the term Yul used to call Mikhail is "Gwanggong" which means crazy obsessed top, or like a yandere seme. I think it's an internet slang used by Koreans mostly in BL media, that's why Mikhail doesn't know the word. And since there's no direct English translation for Gwanggong so I think that's why translators used "Obsessive Maniac"