Scylla and Charybdis were originally taken in as fosters. They were abandoned or orphaned at three weeks old and needed to be bottle fed. The Mom got very attached to them and asked the Dad, "They're so adorable. Can we keep them?"
The Dad replied, "Only if you let me name them."
The Mom thought it over and agreed, "If you stick to girl names, you may name them."
Charybdis was a hungry kitten and could suck down her bottle of kitten formula in nothing flat, which reminded the Dad of the Greek myth of Charybdis who could cause a whirlpool by sucking in the sea, so he named her Charybdis. Scylla was the natural complement to that.
Charybdis is a very active cat and can tear around the house like her tail was on fire, though she doesn't cause the chaos that her sister does. She also likes to climb some, but not nearly as much as Scylla. Charybdis mostly does her climbing outdoors in the tree or jungle gym. She hunts, like her siblings, but isn't as much interested in it as the other two. She loves to pounce Scylla and start a round of kitty wrestling. She also loves to play with toys and anything that she can turn into a toy. She will go on a walk with the Mom and Fenris, when Fenris is on a leash, and she stays ahead of him far enough for her to be comfortably sure that she can't get to her. She has been known to share the couch with Mom and Fenris, with Fenris in Mom's lap and Charybdis on the back of the couch. She is something of a lap kitty and will take any lap that's offered when she's in the mood.
Charybdis is the cautious one.
Though she thinks Fenris could be fun,
When him too close she'll see,
She'll puff up and flee.
She wants both to play and to run.