Marvel Universe: The End (2003 series) #4

Pharaoh Akhenaten has returned and conquered the Earth with godlike power given him by the alien Celestial Order. Most superheroes are dead. Dr Doom went back in time to kill mortal Akhenaten but super-Akhenaten stopped him. But Thanos, Captain Marvel (Genis-Vell) and the original Defenders (Dr Strange, Hulk, Silver Surfer and Sub-Mariner) are trying to destroy the source of his power called the Heart Of The Universe.

A future Thanos is relating the story. He had secretly intended to get the power for himself, not knowing where it would lead him.

His team have reached where the Celestial Order keep the power source. But they have been discovered by 1 of the Order who is suffused with the power. While his minions attack the being Thanos blasts the control system which channels the power from the Heart to its recipients. But the Order still have stores of power in their bodies and more of them are joining the fight. And the Titan sees his 'comrades' fall 1 by 1 until only CM, Hulk and SS remain. So Thanos dives into the energy of the Heart itself.

The voiceover tells us that he'd theorised that the Order used a machine to deliver the power to them because they weren't strong enough to take it directly. But he had experience of holding cosmic power (Cosmic Cube and Infinity Gems) so he figured he could take it. He was wrong and began to disincorporate. We see the Order beings teleport away from the space station which houses the Heart, and it explodes (killing CM, Hulk and SS of course).

But the Titan's willpower enables him to survive and reintegrate. He was battered beyond belief but had no time to rest. He went back to the Valley Of The Kings, 1334 BC, where he sees Dr Doom attempt to kill mortal Akhenaten but get stopped by future super-Akhenaten. But then Thanos intervenes *after* that and takes future-A away through a portal. They fight but Heart-powered A is no match for the Titan who has the *full* power of the Heart. Back in Ancient Egypt the Order's UFO arrives and picks up mortal Akhenaten, but Doom blasts it and it explodes. And elsewhere super-Akhenaten turns into a butterfly(?). Then Thanos goes further back in time to when the mortal alien race discover the Heart Of The Universe and kills the investigating scientists and then wipes the race out with a plague.

The result of all this is that the Cosmic Order never form, Akhenaten never gets alien-abducted and Earth's heroes don't get killed. The Thanos voiceover tells us that some like DrS, CM and SS had a nagging feeling that something was wrong. But the assembly of cosmic beings (Living Tribunal, Eternity & Infinity, Chaos & Order, Hate & Love, In-Betweener, Eon, the Celestials, Thor & Zeus & other gods, Galactus, the Stranger, Mephisto and the Watcher) knew what had happened and didn't like it and would do something about it.