The Preserver was an alien creature that ran a cosmic zoo which housed the rarest creatures in existence: each was the last of its kind. He hired Lobo to capture Superman, the last Kryptonian. However, after getting Superman, he betrayed Lobo and captured him as well since Lobo was the last Czarnian.
For centuries, the Preserver had taken it upon himself to capture and preserve the last of every species in his cosmic zoo. That mission led him to go from planet to planet so that he could find and save as many species as possible. On occasion, he had visited Earth to preserve species from that planet as well.
Superman and Lobo
The Preserver mostly made it a point to capture and contain only non-sentient beings. However, he was not above capturing species if they were the very last of their planets. At some point in time, the Preserver had learned that in spite of the fact that Krypton was destroyed, there was a survivor: Superman. Looking to preserve the last Kryptonian, he called upon Lobo, the last Czarnian, to capture him. After Lobo had managed to capture Superman, he bragged about how he was the last of his kind, which lead the Preserver to place him into his zoo as well.
A very knowledgeable being, the Preserver studied the weaknesses of his "exhibits" and exploited them. He kept Superman under a red sun lamp and Lobo with robots that would discharge a gas that was capable of weakening him. He refused to release his prisoners, and claimed that because they were the last beings from their home worlds, their place was there in his zoo. However, the Preserver hadn't counted on his new exhibits coming up with an escape plan.
After Superman and Lobo escaped, the Preserver sent out security probes to recapture them. Those probes were armed with non-lethal weapons that were used to force the exhibits back into their enclosures. However, after the probes were destroyed, the Preserver grew angry and apparently forgot about his mission to preserve the species. He dropped Superman and Lobo into a pit with a giant snake-like creature that attempted to eat them.
When the duo managed to escape, the Preserver enlisted the aid of Lobo's rival. Gnaww to capture them. However, even after it became apparent that Gnaww and his gang had intended to kill, not capture their targets, the Preserver did nothing.
After he finally decided that he'd have to subdue and capture Lobo and Superman himself, the Preserver went to wait for them in the South Hangar where their vehicles were stored. Upon Lobo's arrival, the Preserver ordered him to return to his enclosure, but when Lobo refused, he transformed into a more powerful being. Apparently losing all desire to preserve both Superman and Lobo, the Preserver attacked them with lethal force, and even tried to impale Superman on his claws. However, during the fight with Superman, Lobo managed to open the hangar doors and the Preserver was sucked out into the vacuum of space.
Afterward, Superman found a new home for all of the Preserver's species in the Fortress of Solitude.
Powers and Abilities
In his regular state, the Preserver was a being capable of defying gravity. He travelled by floating around in the air by no visible means of doing so. He was also capable of generating a force field around his body that repelled an attack from Lobo, but there was no indication if that was of his own ability or a device.
After he transformed, the Preserver seemingly lost his ability to levitate, but gained massive strength and invulnerability. His strength level was on par with that of Superman as he was able to fight him to a virtual standstill, but in spite of his greater size, his strength didn't appear to be that much greater than that of his enemy.
- "The Call, Part II" (Cameo in flashback)