Action Comics Weekly 632
Hal is in space, chasing an alien and his spacecraft. The alien opens a spacewarp in an attempt to escape, Hal is drawn in and ends up in a totally unfamiliar section of space. Heading to a nearby planet to try and get his bearings, the blue alien denies any knowledge of where they are, but suggests Hal visit "his master". Puzzled, Hal heads to the mountain the alien indicated, only to see a giant Green Lantern insignia carved into it. A castle stands on top, and when Hal enters it, he's shocked to discover what appears to be an older human, dressed very much like Alan Scott, wearing a Green Lantern ring and rambling in semi-religious terms. The man identifies himself as Lord Malvolio of the Green Flame.
Hal asks him the way to Earth, and Malvolio reveals he too was born on Earth, and cryptically suggests that it's "beyond Phobos", but he won't say any more. Hal heads out, deciding that he's a "Long winded jerk", but when he goes to inquire of the blue alien about Phobos, Malvolio kills him and accuses him of betrayal, ranting that he brought Hal to this world and he will never leave.

Action Comics Weekly 633
Malvolio rants, and Hal tries to trap him in an energy construct, but Malvolio breaks free easily, revealing that he's studied the green power for four centuries. Hal tries to fight back, but Malvolio outclasses him badly, punching him all the way through the planet, shocking Hal at the power levels the ring is capable of. Seeking to put some distance between Malvolio and himself, he discovers a gold space station. He assumes it was built to keep Malvolio away, but inside he finds a giant Green Lantern battery and more aliens, worshipping it. A man calls his name, and Hal meets Wallace, squire to Malvolio, who reveals that Malvolio killed his father and took the power ring and went off into the universe in search of adventure. There he met Priest (who I remember turning up dead on Oa in GL #1, killed by the Old Timer). Hal observes that they're safe in the yellow space station, but Wallace says theyr'e not safe at all.... just as Malvolio breaks through the wall, having grown in size large enough to grab Hal by the head and hold him, while destroying the yellow space station as a "lesson" to Hal because of his "rebellion".
Action Comics Weekly 634
In the ruins of the space station, Malvolio reveals that he and Priest once engaged in combat, and Priest sealed him up in this starless void. He wants Hal to be his apprentice, renounce his ties with Priest and the "blue skinned god" (the Old Timer) and help defeat them both. Malvolio reveals a lot of his history here, how his father came to Earth in 1612, fell in love with a human woman and he was their child. His mother died in childbirth, and he killed his father and took his ring. He threatens to kill Hal if he turns his back on him again, and mocks him for running, and Hal finally goes on the offensive, knocking him around and pummeling him with his fists, but refusing to kill him, saying his Green Lantern oath means something to him. But Malvolio has another weapon besides his ring, an energy weapon, and he uses it to destroy Hal's ring. Shocked, Hal thinks "this is going to hurt, a lot."
Action Comics Weekly 635
Forced to run once again, Hal makes his way through the space station, trying to keep ahead of Malvolio. He drops into a garbage pit and then finds an armory and collects a harness and massive gun, vowing to do what he has to since Malvolio started it, and he's acting in self-defense. He fires a shot, but having not reckoned with the power of the gun, it walks back and blows a hole in the station. Malvolio seals the hole, vowing Jordan won't escape. Now Malvolio is between Hal and the weapons, but he improvises a bow and arrow, and since everything in the station is yellow, the arrow kills Malvolio. I guess Hal did learn something from Green Arrow about weapons, after all. Hal is sick and empty at having to kill Malvolio. He's stranded with no ring, but decides to take Malvolio's and continue his mission to find the spacecraft he was chasing.
But Malvolio isn't dead. He stands up and pulls out the arrow as soon as Hal is gone. "Everything has gone according to my plan. Hal Jordan, confidante of my eternal enemy, Priest, now sails through the cosmos wearing my power ring. And soon shall the day come that he shall serve me in my war against both Priest and the blue skinned elder God he serves."
Malvolio dissolves "the many illusions" he has employed, and is left alone, standing in the dark.
Interesting story here that adds another (half) human Green Lantern to the mythos, who is extraordinarily long-lived and has power well beyond that of an ordinary Green Lantern. And he apparently had plans for corruption and control of Hal Jordan somehow, since Hal is wearing his ring (which becomes Kyles ring down the road). Back in the 90s when fans were looking for ways to undo the damage to Hal Jordan as a character, this story was one that I saw mentioned as a ready made candidate to explain what happened to Hal, and that perhaps Malvolio influenced him into becoming Parallax. But Geoff Johns has obtained far more mileage from the Parallax as fear entitly concept than he would have from this, so I'll readily admit he came up with a better idea. But this story remains an unresolved plotline from years back that it would be interesting to revisit.