[Well. Her not asking for clarification on what he means is a rather clear indicator she has an idea already of what it might be, isn't it? He's inclined to think he guessed correctly... however much that still doesn't explain what in the world she is.]
And so impossible beings are drawn into it? Perhaps so. Granted, hitherto every "person that should not exist" scenario that I have encountered here has been, shall we say, created by the very impossibility of this world.
[As in, people that should be dead are brought here perfectly alive, although there was nothing "impossible" about them back in their own world. Yet this girl is an impossibility outside of this world too?]