Either over protective "uncle", with a dark history, or a guy trying to use his evil spirit later. He saw the spirit in MC and said nothing. That alone says he probably knows what it is, or at least something about it, and is likely plotting something. Perhaps both...?

Hmm, we're on the same wavelength about that dude, he's definitely pandering to the MC. He definitely has a reason and a goal, maybe he also saw MC above the MC's head and was like shii, I'm a side character, let me stick to him. Possibly overheard the writers saying who the MC was lol.

or maybe he got to liking towards mc 😂 old guy 🤣🤣
why am i thinking this way damn brain stfu

I wonder what mc is trying to sneak out🤔