Melkor Damask braced himself as another large wave crashed down upon the crumbling ruins of the second Death Star, spraying him with a dense cloud of salty mist. The oceans of Kef Bir were much more tumultuous than the story seas on his adopted homeworld of Bal'demnic. The waves were towering, making it deadly for anyone to venture out to the ruins of the fallen superweapon. But Melkor and the Devaronian that stood some ways in front of him were not just anyone. Only those who could command the Force could ever hope to survive out here; and the two of them could command the Force in its purest form. The dark side.
You have come far, my apprentice, the Muun thought as he sized up his pupil, who had indeed come far from the alien plagued by visions that Damask had found in the ruins of the Jedi temple on Devaron. Now, let us see how far.
On the journey to the ocean moon of Endor, Melkor had already explained the terms of this test. Neither were to kill or maim the other. Merely attempt to best the other—to back his opponent into a corner and force them to yield. After all, Melkor had not simply chosen the Death Star's ruins for the scenery. He was, at his heart, a collector, and these old ruins had secrets that had yet to be plundered. Other than those restrictions, however, there were no others. The entire ruins of the Death Star were fair game as their battlefield. What Melkor had kept from his student was that the dark side of the Force was strong here. After all, it was where the last two Sith Lords had died over a century ago.
Those who visited these ruins and survived the climb tended to experience... phantasms. And that was the true test. To see if his pupil really had overcome that which had once unmade him. Only time would tell. The Muun allowed the cylinder of his lightsaber to slide from his drenched right sleeve and into his hand, where he ignited it, a crimson blade spearing through yet another spray of ocean water. And then he steeled himself, wrapping his body in the dark side of the Force—this was going to be as much a test for him as it was going to be for his apprentice. @Arclight