Yeah. At the very least we'd scorch the earth before we'd let them pry it from our cold, dead hands.

I think you need to calm down. It's your theory, but by posting it on here, you're leaving it open to criticism and scrutiny. Please don't be mean about it, it makes you look bad. You have a right to, yes, but that doesn't solve anything. Be nice about it.

Yes, planets do move, but it moves in an orbit around a star. It doesn't just move in space, it would be frozen over completely by now if it did, with all of its inhabitants turned into ice cubes and dead. Including the Gremlins, seeing as Outer Space is -454 degrees Fahrenheit. The core could certainly supply energy though, so there's nothing wrong with that theory, apart from the fact it would take billions upon trillions of years to even get into the Solar System, though we have no idea where Cradle is relative to it. You can't just "make a trip" to a place that takes eons to get to. Gremlins might have had FTL (Faster Than Light) travel, but they would have wiped out the Knights easily by now, or sent them on their way.

Also, there's a huge problem with your second point. You didn't even explain the correlation to Isora and technological advances. Strictly speaking, we know absolutely nothing about Isora, much less the history of Knight technology. So, you can't really make any assumptions from that. Here on Earth, we have guns that can shoot particles several thousand miles per hour (railguns), bombs that can utterly destroy cities, kill thousands in an instant, and make sure that place will be uninhabitable for years to come, and an increasingly large number of ways to kill people en masse. Anyway, you've probably gotten my point by now. You can't assume things without facts.

Please act more civilized here in the future, and work on your arguments as well. Thank you.

It is true, if you think about it in someways, I mean we don't know much about how gremlins or fiends live, but it is somewhat apparent that whatever used that ruined city builds in an approach greatly to that of a 'human' like style. However, now we look at the barrier between fiction and reality, where we can, in some ways, say that the buildings found in Haven, The Fire-Storm Citadel, and in-fact any place that has buildings in game look the same, but really Aekuryi is right saying it looks like a city belonging to some sort of 'peoples'. Another game loophole is that really, the whole place is a mystery, you're looking at the Gremlins, who sort of 'only recently' developed the power of the Roaries. But once again, this really is all speculation based on how you see things.

EDIT: Then again, thinking, there is very little possibility as to how the gremlins would have been able to destroy the Earth. Perhaps they attacked in the past? You look at the buildings, and it looks like stone or concrete, not metal and glass. Or even, we might not even say that the gremlins touched the earth or has anything to do with transporting chunks of it to Cradle, I mean the place is a giant clock-thing powered by an impenetrable Core! The entire thing doesn't even make sense lol, the weight of the gears and everything could possibly collapse and crush Cradle together. Yay for scrutinizing the details of video games!!! :D Man, we just shouldn't call them video games anymore lol, online games....

/yes