There is a space at the bottom of the world, where Earth and Ice and Shadow meet. It is cold, but not cold enough to kill; dark, but not too dark to see. A small round room, made of chilly black marble, lit by a dim and sourceless glow, with a spiral stair climbing the curve of the wall and a shallow circular recession in the exact center of the floor. The recession is maybe six feet wide by six inches deep, lined with something resembling pale frosted glass, and there is nothing in it.
"A rock with no middle? Why?"
"Vacuum is like blood and ash but harder to come by."
"Ooh, huh. I admit I'm having a hard time picturing how you'd manage to paint with it. Especially if you couldn't make arbitrarily shaped things and then remove their middles. Do you just sort of... put it... near paintings...?"
"Pretty much, yeah. You orient the paintings that call for it around your vacuum."
"Makes sense, I guess. And opens up all sorts of interesting possibilities once you can make arbitrarily shaped vacuum objects."
"It really does! We'll need a dumping ground, though."
"Yeah. Hmm, I wonder what happens if you throw a disappearance point into Void or Chaos... you'd have a bad time trying to ever find it again, though..."
"And you do have to find it to attach a mage to it."
"I guess there's nothing stopping you from putting a disappearance point on a surface new every time, attaching one or a batch of mages to it, and chucking the point out the window until next time you need to mage somebody?"
"If they bumped along just fine through Chaos without eating any worlds I'd be tempted. But that seems like the sort of thing that would be hard to test."
"Yeah, and I don't think we have the theoretical backing to justify trying it without."
"Untrustworthy magic systems are nobody's friend!"
"Always remember to check your magic system's references!"
"If we do have to stop using mine I'm gonna miss it." Sigh.
"I bet. Although if it were me I think I might be too irritated about its untrustworthiness to want to keep using it once I had alternatives."
"It's not personal, I don't think. And you can argue that we should've seen it coming."
"On account of having to cast spells by chanting about destroying. Also disappearance points look horrid to nonmages."
"Okay, that's fair."
"Wonder if I can void disappearance points."
"...oh now that's an interesting notion."
"The current interworld transit method leaves something to be desired in terms of my comfort level with making major changes to the structure of a planet while I stand on it. I suppose it'd help if I brought a swoop and wasn't in range of earthquakes?"
"Yeah. And there's that zooming thing."