I just unlocked her app in her journal. So you should be able to see it!

Alrighty. o; If you want to watch a play through I'd go with Cry's honestly. That's how I got into Ib. XD

First thing you need to know really is... Mary is not human! Surprise! She's a painting from the gallery. One of the endings is kind of Pinnocio-ish where she becomes Ib's sister. (Ib forgets everything that happened and Garry dies so horror game.) The fandom either hates her or pity-loves her. There's barley any middle ground. ):