Not really a surprise since it's an Asian trope, but Mr. Squinty is going to turn on them (squinty eyes usually always means sus). He is in league with Terenezza.
I had a feeling he was Bad （￣へ￣）IF BAD WHY HOT but I Wonder the way Diana looked towards him was kinda sus, did he threaten her or something?(⊙…⊙ )
Not sure. I don't read Japanese. I just saw the raws.
The reason why he is attractive is likely because of the source of the trope. However, not all squinty eyes are attractive. Not all are antagonistic. Sometimes it just means they like to prank people.
The whole squinty eyes thing comes from foxes and, according to most Asian cultures, are sneaky, mischievous and intelligent (think Loki). So when a character has those kinds of eyes, it usually (but not always) means they are up to something.
Any spoilers(⌒▽⌒)?