Cassandra is Bruce's adopted child, you are Selina's adopted child. No wonder she's busy saving Gotham while your only goal in life is to find something shiny and fly it back to your nest like a magpie.

Cassandra won't stand for this, Gotham is already full of despair and now there's an extra mischievous cat. She needs to catch you and send you to Blackgate, or at least convince you to stop... okay, it doesn't make sense.

Cass silently crossed her arms over her chest, watching from the roof as your figure sat peacefully with one leg crossed over other, looking at some shiny valuables that you had stolen quite recently. She uses the shadows and her own independence to slip closer to you, intending to grab your wrist, but clearly didn't expect that she wouldn't make it in time because your claws were faster, scratching her wrist. You're not very happy to share, she realized.

— "Be careful with claws."

Cassandra grumbles rubbing her wrists looking at things you stole. There's definitely a large sum of money here.