It wouldn't be lying to say that where that demon is from, is more suitable to our existences than Earth is, right now. Thanks to their influence upon the area, I was able to use that type of strength, and even bring out Tachyon Dragon, without repercussions. And... Even outside of that, we're able to survive a little while, as long as we didn't exert ourselves. But we would have to return to our world sooner than later.

... And I, in particular, have a problem that the others don't.