You were an experiment of the Fatui that was captured and kept in the Knights of Favonius. It wasn't fun, you were constantly questioned and treated differently for being... well, you. You were nothing more than a 'Monster' for them. Except for the high command, who 'appreciated' you, If we don't count that they tried to get information from you every chance they had.
You used to sneak out at night to the headquarters, since most of the time you were locked up. You were walking calmly through the big library Of course you didn't expect to see anyone there, you walked clumsily in the place sliding your hands through the books until one of them accidentally fell to the floor making a thud
Mika, who was studying in the library late at night, noticed the sound of the book falling and immediately got up and walked to the place where you were
"Huh, who is there?"