Unfortunately, she forgets that she outweighs them by a fair amount.
She caught Mary and landed on her with her front two paws. Mary didn't care for this and hissed, at which point Pi hissed. She's back to not liking the kittens so much, though she's certainly better than when she first met them. It didn't help when I was tossing some paper wads to her and the kittens decided to join the game... Pi wasn't too happy about that either. But still, things are looking up!