Foxy lady
Her character is NOT a "mary sue" as others may put it. There are a lot of "Sungji" in the 2D world. Rare, but they exist. Eccentrics are.
I know I mentioned this before, mainly because her only faults at the time would make people like her more. Her social obliviousness is technically a fault, but it's a cute one, if you get what I mean? She is also loved by anyone who sees her, even Sumin admitted it is hard to not like her when you meet her in the last chapter.
However, these recent chapters have emphasized or made obvious traits of her that were more subtle or "not spoonfed" in past chapters. She is nervous, insecure, and jealous. Jealously is something not seen favorably in most cases, so you are right, she is not a "Mary Sue," so I stand corrected. She is more realistic.
I know Sumin says Sungji is like a puppy in chapter 85. Is that a good thing in a relationship?
What do you think makes Seju an INFJ?