Phosphorus and Kasein

Two thoughts I've had that I decided to make into actual characters. They're kind of ridiculous.
I've wanted to name a character after casein for a while, because it's such a great word. Makes a good name. (It's milk protein, btw. I'm allergic to it which is why I know the name. xD)
Phosphorus, as I've found today on wikipedia, is another component of milk. It also glows in the dark sometimes. So yes.
I have no idea what sort of story they will be placed in as of yet. Whatever suits my fancy. x3
If Phosphorus looks familiar, it's probably because of this:

I decided to turn that design into a real character! I liked it a lot.


In a few words of description:
Phosphorus (purple hair) is graceful, coordinated, and mature.
Kasein (pink hair), in comparison, is strong, chaotic and naive.
They both excel at fighting, Phosphorus preferring more hand-to-hand combat, and Kasein preferring weaponry. If she carries one, Phosphorus prefers a long, light sword. (like a katana)

I'm not sure where I want to go with their skills, could be anywhere from modern-day martial arts geeks to alt. universe girls to time travelers to pre-apocolyptic paranoids preparing for the zombie apocalypse.