I really don't want to level my magic but I wanna be a vampire lord, anyone know if while in the transformation do you use magica? Any answers appreciated!

No. But you will find out for yourself soon...

Thats a good question. Maybe watch the gameplay videos again and check and see if magica depletes as the vamp lord is casting.

I only know about the game spot one and there's text covering where the magica bar is, so I can't tell..