No, not consumes a world, the maiden that Allison swapped places with said that each time Mottom visited their world she called 100 maidens to her palace to 'serve' her.
http://killsixbilliondemons.com/comi...of-names-3-51/
I was guessing that she visits a different world every 3-4 days, and at each visit picks up another 100. But even if she visits a different one every single day that's still only 36,500 a year. I mean sure, that's bad, but in the grand scheme of hundreds of worlds frankly its really not that many.
Again, while yes its pretty terrible, on a scale of 1-10 on things that could potentially be happening to them this is about a 3. I was honestly expecting them to be served up and eaten alive by Mottom or something along those lines.