In certain respects, it could be said that the void itself was the immortal plane while the bubble worlds were the invaders as opposed to that being said of the void beasts.
Either way, with a bubble world right here, Dyon didn't need to go out and search for the perfect asteroid. In addition, since this world wasn't destroyed, the sturdiest parts of it – around the world core – were still intact.
In other cases, when the bubble world imploded, the world core would be the first to go, so the precious ores around it would suffer the greatest. In fact, what Dyon was doing now – targeting a healthy world – was exactly what those who created the most powerful of graveyards did.
However, compared to them, Dyon was a level better. Who had ever heard of a world core being so peaceful…? And even further, who had ever heard of using a world core's energy to forge a graveyard?