I would hold back on calling her a little monster
and try to be empathetic. Of all children, kids who live these types of experiences need gentle, nurturing care more so than your average. You need to always stay calm with her and try to provide some stability. Sadly, I'm guessing this is truly temporary and her life will be upheaved again soon. While she is with you, you can provide a loving and caring household. Good for you for taking her in even though it is hard.