Osage-chan is a Japanese schoolgirl who sings. She has twintails. She rides the train to school. She also likes Vocaloid.

Yes, this is indeed the Lagtrain girl.

A caffeine-addicted tomboyish shark-girl who likes to draw, make songs, play games (mostly rhythm games), and likes a lot of VTubers, but very has a very unhinged personality, but is sometimes very sweet (this is not 100% accurate irl).
They would often times comfort someone when they are distressed, or jokingly make fun of someone for doing something idiotic.
Also, they seem like a certain individual named Medic, and will be flustered if they ever hear that name mentioned anytime.