The world on which the M'krann Crystal sat was not round, nor had it evolved naturally. The unknown beings which had created the M'krann Crystal, uncountable eons ago, had made a special world for it, one that was flat, looking like a continental plate that had been lifted from a normal planet and set rotating in space. Those same beings, of whom no sentient knew (or claimed to know) anything (but who it was rumored had been the near-legendary Founders themselves) (others, who had reason to believe differently, claimed that those who had created the M'krann and its resting place were the almost-mythical Makers) had ringed the "world" of the M'krann with all manner of magical shields and spells, and had placed many technological devices above it, to remove the world of the M'krann from any prying eyes or from those who might discover it. But the eons had not been kind to those devices, and endless assaults on the shielding spells had worn them away, until the world of the M'krann had been on the verge of being exposed to the universe - most of whose natives, of course, had not heard of the M'krann, and those who had, had no idea where it was, and lacked the resources to find it. But some few had heard of it, and knew how to find it, and were physically capable of finding it.
And so it had taken only one (admittedly quite powerful) spell, by a skilled and mighty mage, to undo the final defenses of the world of the M'krann, and lay it open to the universe, and the multiverse.
Of course, other beings had known of Der Zauberer's intent, and his spell, and had been waiting for him - some for years, or decades, or centuries. Some of those beings, assigned by Higher Powers to the maintenance and defense of the universe or the multiverse or some aspect thereof, or having volunteered for such a duty, wished only for the M'krann to be left alone. Most other beings who had been waiting for this moment, however, greatly desired to gain control of the Crystal, usually for deadly and evil ends.
Not all of those beings, good or bad, came to the world of the M'krann from the same relative time as Der Zauberer. Some, having foreseen the future with magical or scientific means, had traveled forward in time, to be present at this moment. Others journeyed backwards in time, having known for shorter or longer periods that such an event would take place, and waiting for their own powers to wax or for the relative "now" of Der Zauberer's spell to come to pass.
The moment that Der Zauberer's spell had burst through the shielding spells around the world of the M'krann and opened up the gate to the world from the Earth, a number of beings from the past and the future had seized on his spell, and through mental or technological or magical means had pushed the spell backwards in time, through the Fourth Dimension, so as to undo the shielding spells before Der Zauberer could, and had driven the spell 5 minutes into the past, so that the defensive shielding spells around the Crystal were undone before Der Zauberer had started casting, and so, when Der Zauberer dragged himself through the open gateway, there were many other beings already on the world, battling with the last, inner defenses of the Crystal.