I can’t believe I’m doing this, but…

A few years ago, I found a graphic novel I really liked. Problem is, I’ve bought two new computers since then, so I lost my bookmark to the comic, and I eventually forgot about it.
Now I’m looking for it again. My hopes are a little extreme of finding it.

So here’s roughly what I know : The characters are all Anthropomorphic. At the beginning of the comic, a girl (I believe it was a cat…) is sacrificed. She’s pulled up by chains high in the air and a spear impels straight through her, as some sort of hex circle starts to glow. Then the comic shifts to a cat and his alien-pet thing that can magically levitate in a class room, I don’t remember how, but he (the cat) ends up in a shaft and runs into a girl of a species I’m not sure about. (She’s purple, though. I do remember that.)

And now some other points :
The setting is in a futuristic alien world, with a city.
The purple-girl-thing is one of two daughters of a rich man. (possibly a mayor or noble rich person of some sort.)
The cat (I believe) is from an orphanage run by a shark. The shark uses the orphans as (illegal?) labor.
The comic was going to be an animated feature, (the animation can be found on the webpage) but it was then turned into a graphic novel.

I’m not asking anyone to scout for this thing. But if it sounds familiar in a way, just let me know.