A third son of prophecy (Harry Potter AU / Assassin's Creed lore)

Harry Potter with many changes to canon. Hogwarts doesn't start at 11 but three years later and that is by far the biggest change, which brings many other changes naturally with it. First years are older and more mature, but also more headstrong and set in their ways. Seventh years are 20-22 and therefore pretty much college-aged. Harry will have lived with his abusive relatives for three more years. Hermione will be more socially awkward at first, but also more determined to be smarter than everyone. Ron will be more of an insufferable twat because he was with his twin brothers for longer. ----- My MC will be born with knowledge of the Harry Potter franchise and, which he will find out gradually, a special bloodline. He will not have knowledge of the Assassin's Creed games, but I will tell you now, he will have the Isu bloodline like Altair, Ezio, and Desmond - just from a different Isu 'god'. Geographically, I settled on the Norse Pantheon instead of the Roman one like Desmond's lineage, and his magic gives my MC the natural ability to dream of the lives of his ancestors, so he doesn't need an Animus to do it. Any AC plotlines will come much, much later. The modern brotherhood and the templars will not be outwardly knowledgeable about magic, because I don't care to write all the consequences that would bring with it. But the Mentor (leader of the Brotherhood) and the Templar Council will probably know about magic regardless. (Just don't think about it.) MC will hate Dumbledore and fully assumes him to be a secret Dark Lord, which might or might not be true - but by the circumstances of his birth and upbringing, Dumbledore will have certainly earned the animosity the MC feels. All rights to the story's many elements like Harry Potter and the Assassin's Creed lore belong to their respective owners.