A Massive Multiplayer Crossover by Nimbus Llewelyn that started on the What If? that The Mighty Thor had been incarnated as James Potter, as a first run on that humility thing. Oh, and after he died, he went mad with grief and Odin had to wipe his memories. Then those memories were restored by Loki in Harry Potter's third year at Hogwarts.
The result is a world of strange hijinks, constant snarking, lots of badassery, evil plots, Loads and Loads of Characters, creepy super zombies lead by an even creepier necromancer, and Loki's incredible coffee making skills. The sequel piles on more weirdness. While the premise of Harry turning out to be the son of a Norse god and being given sudden superpowers is a typical Marty Stu setup, the story avoids becoming Wish-Fulfillment by exploring the issues it causes both for him and the wider world. The story also has a lot of Worldbuilding on a large scale.
The author has alternately stated that the entire series is mapped out beforehand, or that he changes his mind at the last minute. He cites as inspiration Smallville and X-Men: Evolution, which similarly start with a youth discovering their powers and the issues that comes with them, and The Last Son series and SmallvilleX: Evolution. He's also friends with the authors of The Magic of Torchwood and De-Aged, crediting the former as a key beta/source of advice and the latter as an invaluable source of scientific expertise.
Has four instalments so far:
- Book 1: Child of the Storm, which starts it all with Harry discovering his heritage and, essentially, trying very hard not to die as a lot of people try just as hard to kill him, while discovering new powers and making new friends, all while HYDRA ascend, the Darkhold whispers and everyone dances on the puppet strings of the Sorcerer Supreme... It is complete, and can also be found on AO3.
- Book 1.5: Chaos Reigns, is a side story set just prior to chapters 59 and 60, alternately from the POV of Harry Dresden and Wanda Maximoff, as they handle an incursion by the demonic N'Garai. It is complete, and can also be found on AO3.
- Book 2: Ghosts of the Past, follows on from the Final Battle of Child of the Storm with Harry starting to assert himself as a Power in his own right, but one still vulnerable thanks to his nature as a Glass Cannon and his inexperience, and dealing with the reverberations of the events of the previous book. Meanwhile, a number of separate villains are all, for one reason or another, out to either control him or to destroy him. It is ongoing, and the first arc (Prelude) and the start of the second (Forever Red) can also be found on AO3 note
- Book 2.5: Unfinished Business, is a side story in the vein of Chaos Reigns, similarly set with a Switching P.O.V. (this time, initially Carol and Peter's), around chapter 62-65 of Ghosts, when on a school trip to New Orleans, some very particular ghosts come back to haunt them... It is complete.
Has also gained a certain amount of recognition beyond this page and recommendations on this site:
- An incomplete reading, the first several chapters of which can be found here.
- It is also being translated into Russian.