Someday I have to write down everything I know about Archipeligan magic and how it works. For now however, I'm delivering it in bite-size chunks that are vaguely related to the current pages. Today's topic is: Why does Vaniji's magic looks like hands, smoke, and snakes, and for that matter why does magic take on different shapes for different people?
Answer: It's hard to descripe WHY it does this (it's nearly impossible to predict WHY magic does ANYTHING) but there's been some research into how. Magic in it's original form is without shape, and for new magic users or the inexperienced (such as Credenza) it manifests as whirling shapeless matter. However, as a magic user becomes more adept as their powers, they subconsciously start to mold their magic into various shapes, usually manifesting how they view their magic or what they want from it. For instance, Alice views her magic as something within herself that flows through her like roots through the ground, and it manifests as patterns on her skin (this view also makes it difficult for her to use her magic to any outward purpose). Vaniji on the other hand grew up with magic, his mother being a witch who specialized in illegal magic. As much as he hated her he admired and craved her power, and as his magic talent grew it shaped itself into things he associated with that power, the smoke his mother's potions gave off, her gnarly scarred hands, and the numerous pet snakes she kept.
He's aware that this is why his magic looks like it does, but since it's subconscious he can't change its shape, however much he wants to.