The Crystal realm was a vast land. When Lex first arrived in the Crystal realm, it was approximately the same size as the entire solar system. Starting from the sun in the center, to far beyond the limits of even Pluto, the solar system had so much space that a million lifetimes would not be enough for Lex to traverse all of it if he did so normally.
Since then, the Crystal realm had grown in size by about 30 - 40% in total, though the exact growth could not be easily estimated.
But Lex already had a record of teleporting a distance much, much greater than a mere star system, so for him to teleport anywhere within the Crystal realm was not a problem at all.
So, from within the temple, Lex teleported over to a place that, from the birth of the Crystal realm, had never been witnessed by any being other than a monster.
It was the absolute depths of the realm, where not even a flicker of light had ever been witnessed, and thus was home to the strongest and oldest monsters.
