User blog comment:PB&Jotterisnumber1/Fan considered theme songs for characters/@comment-5932670-20180627191347

Maria Tachimi would be Learn to be Lonely from Phantom of the Opera, as a ghost until her appeasement, her only companions were her action figures.

So, basically, she was a variant of Lonely Doll Girl, her Transformers action figures were the only things she was capable of talking to.