All-Father Thor's History
In preparation to take over the last realm standing in the War of the Realms, Malekith trapped Thor in Jotunheim before mobilizing his troops to Midgard. Earth's heroes mounted a counter-offensive, and as part of their efforts, Freyja sent a team of heroes to retrieve Thor from the Land of the Giants. Once back in Midgard, Thor led the final efforts to fend off the invading forces while trying to find Malekith, who had kidnapped Freyja and Odin.
Malekith challenged Thor to fight him at Stonehenge, where he had erected a magic barrier that would kill his parents if anybody other than Thor passed through. In order to find a way to overcome Malekith's challenge, Thor nailed himself to Yggdrasil, which had taken root in the Sun. After sacrificing his left eye and the last shards of Mjolnir in his possession, Thor figured to recruit his older and younger self with whom he had defeated Gorr the God-Butcher. They were joined by Jane Foster, temporarily returned to her Thor form by the reconstituted hammer of the War Thor. During battle against Malekith, who had empowered himself with the Venom symbiote, the God Tempest manifested in the Sun, and Thor commanded it from Earth to reforge Mjolnir. The hammer then made landfall in front of Thor and he managed to lift it, having become worthy again after coming to the realization that his struggle to become worthy in itself was what made him worthy. Thor used his returned hammer to deliver the final blow that defeated Malekith. For proving instrumental in defeating Malekith and saving Midgard, Odin stepped down as the Asgardians' All-Father and appointed Thor as the new All-Father.
Battle of the Black Winter
A few months after his coronation, Thor began feeling dissatisfied with being the King of Asgard, missing his glory days as a hero; with both Sif and Loki taking note of his desire to shirk his duties and that Mjolnir was becoming heavier. Thor's melancholy was interrupted when a badly-injured Galactus crash-landed into Asgard. Thor initially attacked the World-Devourer, but was told that he faced a much greater threat: the coming of the Black Winter.
Gathering Galactus' former heralds, Thor was informed by the Silver Surfer that the Black Winter had destroyed the 6th iteration of the universe, and if Galactus was going to be powerful enough to oppose it, he had to consume five special planets. Thor prepared a fleet to evacuate those planets in preparation for Galactus devouring them, but was stopped by the World-Devourer telling him that the Black Winter had shown him that Thor was to be his death. Stating that he would keep a close watch over Thor from then-on, Galactus imbued him with the Power Cosmic and turned him into a Herald. Thor led Galactus to the five planets, provoking a skirmish with Beta-Ray Bill that resulted in Stormbreaker being destroyed, but when they arrived on the final planet the Black Winter attacked them. Enraged that Galactus devoured the planet without giving him time to evacuate its residents, Thor promised a reckoning after the Black Winter was dealt with.
Confronting the Black Winter, Thor was forced to confront shades of his greatest enemies but managed to drive it back; learning from the Abstract Entity that Galactus was in fact its herald and had been lying to Thor in the hopes of avoiding being forced to serve it. Furious, Thor stripped Galactus of the power he had acquired from devouring the five planets. When Galactus tried to attack him, Thor drained him of the Power Cosmic - leaving him a desiccated husk - and then used the dead Devourer of Worlds as a bomb to destroy the Black Winter.
Prey
Traumatized by a vision of his possible death at the hands of Thanos, Thor withdrew into his throne room and spent the next several months drowning his sorrows in copious amounts of alcohol, only breaking his silence when comforted by the Silver Surfer. Deciding to see what was wrong with Mjolnir, Thor dropped it in Broxton to confirm his theory that everyone was worthy of wielding it. Thor also apologized to Bill for their fight and the destruction of Stormbreaker, and appointed him his advisor and offered him a new divine weapon from Asgard's armory. Once his theory was proven correct, Thor reclaimed Mjolnir and sought answers on how to repair its enchantment by swapping places with Dr. Donald Blake. Once inside the illusory world Blake had been placed in, Thor was horrified to discover that Blake had gone insane and was hellbent on destroying everything Odin had created; trapping Thor in the illusory world and then going on a killing spree in Asgard.
While Blake banished many of Thor's allies to the Dimension Blood and attacked those who carried the power of Thor, Thor remained trapped in Blake's illusionary world. When Blake began cutting down Yggdrasil with Jarnbjorn, Thor had had enough and called out to the ravens Munun and Hugin and asked them for their help. Thor knew that while he couldn't leave Blake's world physically, he could separate his spirit from his body and leave that way with help from his ravens. Needing a vessel to put his spirit into, Thor chose the Destroyer Armor and confronted a shocked Blake.
With help from his allies, Thor defeated Blake. Odin was about to put an end to Blake, but he was stopped by Thor when he was handed a piece of Blake's broken walking stick and used it to return from Blake's realm. Thor decided to spare Blake's life as he considered him his brother but did punish him by striking him with lightning. Thor then allowed Loki to deal with Blake.
