My characters generally portray thoughts that go on in my mind, not my actions. (I'm the calm, quiet type who can practically become invisible. I only need a spell for true invisibility.)
Luper is the part of my that refuses to take things for granted and also my belief that nothing is as perfect as some people want me to think. Some of my arrogance is also there, but Luper is far worse than me at that. He's also the rude part of me. (This part never gets to speak in real life. Unfortunately, my social position means I only get trouble from insulting people.)
Aureus Lucis is the part of me that believes that brains are better than big muscles. Yes, he's strong as a vampire but if you watch him in the Cursed Blood, you'll notice he relies more on spells. And he's got style, is polite and always (or almost always) calm. I'm the same, only I lack the style.