Voldemort sent his mind forward in time for a tactical advantage against Harry Potter. He takes over Harry's adopted grandson, Harry Lupin, and secretly plots a covert war to take over both the wizarding and muggle worlds. Harry Lupin is part werewolf and part veela, not to mention being a metamorphmagus. His first year at Hogwarts is going to include the Quidditch World Cup, Triwizard Tournament, a mass exodus from Azkaban, possession, and rivalry. So far anyway...
He stared out the window of the Shrieking Shack, lost in thought. His plans were in full motion, soon the stage would be set. He smiled while he thought of his contingency plan one last time before initiating phase one, so the boy wouldn’t learn of it. The torn apart furniture and claw marked floor gave a sense of foreboding to the dilapidated building on the outskirts of Hogsmeade. The atmosphere was intensifying his mood, preparing him for the inevitable. Acting had always been his strong suite, but this was something different altogether. To purposefully sacrifice oneself to further your own goal was invigorating. Now he knew why those that opposed him did it so often. Of course, none of them could even hope to do what he’d done, but it was the thought that counted.
His strange connection with Harry Potter was an aggravating annoyance but occasionally a nice surprise. Through this connection he learned of the Deathly Hallows, though this was most likely how the boy discovered his greatest secret. Either that, or the old man suspected that he’d created Horcruxes and told the inept boy. His smile grew as he thought about the absurdity of his situation. To be brought to the brink of absolute death by an insane old man who is currently deceased and a young boy whose survival was based entirely upon luck and his mentor’s alliances.
He sighed, and in tantalizing trepidation, quietly pointed the Elder Wand to his temple. Voldemort slowly pulled the glowing silver strand out of his head and said an ancient spell inaudibly, just in case Lord Potter was nearby with his blasted invisibility cloak. The spell was one of the longest and most complicated spells he’d ever performed. As the memory whisked away in the calm night air, he looked about the room one final time. He felt a significant drain on his body. Converting one’s entire persona into a magical incantation, sending that into the future, creating a newer and dumber persona, and placing that persona in the original body would kill any normal wizard. It would only cost him ten minutes of fatigue, then he would perceive a few seconds passing then he would be in the future.
This was his greatest plan yet, and nobody would ever suspect it. It was unheard of for somebody to sever their mind from their body and place a fake mind in the body. It was inconceivable that the same wizard would then place their mind in suspended animation for years while their body decayed. Of course somebody in the past could have done this, but that was very unlikely. After all, Lord Voldemort pushed the bounds of magic further than they’d ever been pushed before in so many areas, why not add time travel to the list? This was the perfect opportunity for vengeance, he had quite the element of surprise.
His mind would latch onto somebody close to Potter, preferably family member of his. It would be best to possess a young child since they would be easier to take over and less suspicious. Who would suspect a teenager of having the powers of a Dark Lord? Of course, underestimating Harry Potter had been his undoing in the past, but this time he would be the unexpected winner. From there, he would gather evidence of Potter’s strange powers from within the family and kill him. He would regain the Elder Wand, inherit the invisibility cloak, begin making new horcruxes using the child’s soul, and start forming a new army of Death Eaters out of other students at Hogwarts. Voldemort smiled at his dastardly plan.
Then the spell was completed and he blinked his red eyes in confusion for a second, and then raised his new wand to his throat. The siege of Hogwarts was about to begin, but not before he gave them a chance to surrender Potter to him. Very clearly, he said, “SONARIS!” and gave his speech to the warriors of Hogwarts.