Harry gaped in horror. "There was something in my head?!"
"There is no need to thank me for ridding you of it. I now reside within you instead, and you are the only one who can see and communicate with me, thus why I am talking to you."
"There's a god living inside my head?" asked Harry, not looking any less horrified.
Loki frowned, slightly offended. Whilst that was greatly overly-simplified, it was essentially the truth. "Yes. Oh, you also happen to be a wizard."
"Magic is real?!"
Loki raised a single eyebrow. "You so easily believe in the gods, yet magic is infeasible to you?"
"Well, Vernon and Petunia say—" began Harry, but he was promptly interrupted.
"Vernon and Petunia? The same aunt and uncle who hate you?" Loki said, and Harry recoiled in surprise. "I live inside your head, Harry, I see the world through your eyes, and I know hatred when I see it. I have faced it many times before."
Harry frowned. "But you're a god."
Loki's expression saddened an almost unperceivable amount. "Even gods have families, Harry." His eyes glinted as a smirk broke upon his face.
"On that note, you must soon begin to learn magic if we are to leave this place, and I think your family would make simply excellent test subjects."
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Harry let himself drift away from reality, concentrating on nothing but Loki's telepathic instructions and his target, Dudley.
The sounds of the school playground faded into numb static as Loki's voice became the only noise perceptible to him.
"Look at Dudley, then look beyond him. Stare upon his form in both body and spirit, and then push yourself forward," Loki whispered.
He had told Harry that whilst there were many ways to invade someone's mind, this would be the easiest by far with him helping, also simplified by the fact he was only trying to intrude upon a weak-minded child who had no innate magic to fight off invasion.
It was not a mortal method, but it was one Loki himself had been quite adept at using when he himself had been young.
It had taken him quite a while to learn as a child, but he could dramatically speed the process for Harry by doing the heavy lifting himself. There was also the matter of how much weaker a mortal mind was than that of an Asgardian.
Harry followed Loki's advice to the letter, piggybacking off the Asgardian's soul to perceive more than any human could, and when he moved forward, his body did not.
A portion of his mind merged with Loki's lashed towards Dudley at amazing speed, colliding with his mind.
With Loki focusing on enhancing Harry's perception rather than instructing him, Harry might have had a difficult time trying to dominate Dudley's will. Luckily for him, he only needed to influence his mind.
Gathering all the hate he had for the boy, Harry manifested it into existence, imparting upon Dudley the first thing that came to mind.
This method was in no way delicate, relying on emotion, but it could work well in some instances.
Satisfaction flared within Harry as Dudley let out a scream of terror, no doubt a result of the wave of spiders he was currently imagining flooding across his vision.
All of Dudley's friends laughed at the fat boy, who was still screaming even though the weak illusion had undoubtedly dispersed by this point.
Later, when the excitement had died down, Dudley glared at Harry, who promptly swallowed. If Dudley suspected his freakishness to be at hand, Harry would be in trouble with Vernon and Petunia, evidence or not.
'Well,' began Loki, speaking directly into Harry's mind. 'I suppose my next lesson should be self-defence.' He paused. 'I believe that my being torn apart may have limited my ability to plan things. Being torn apart does tend to have that effect.'
Harry was a quick learner, no doubt. Projecting your mind forward like that was no small feat for a human.
From the ease with which Loki had managed to help Harry do it and see the world on a supernatural level, he thought that he might have already merged with the boy at least partially, making Harry's magic slightly Asgardian in nature. Now there was no chance of separation, not that there had been to begin with.
Whilst the magic of Asgard flowed through Harry, Loki suspected that his power levels were nowhere near that of an Asgardian if the fact that he had been exhausted by that small illusion was to say anything.
Loki might be able to fix that in the future, though he really had no idea. It was completely unheard of for a being of his complexity to live within a mortal's mind.
He had hoped he would be able to channel his whole power through the boy, but it was apparently not to be.
He could push his mental force into helping Harry perform a spell, but not his magical strength; that part was down to Harry.
With him guiding Harry's magical, mental, and physical development, however, he was sure that he could make some changes for the better—like, for example, making him into an inhuman and immoral and preferably not completely insane psychopath.
If he wanted to ensure that the boy— and thus he—didn't die, the first area he would need to work on would be his personality.
It would not take much of a push to turn an abused and neglected child into a cold-blooded and ruthless killer, and Loki spoke that from experience.
Dudley knowing the illusion had something to do with Harry had been an unpredicted gift. The boy would fear approaching Harry, being the coward he was, and would instead run to his parents, giving Harry a good amount of time to recharge.
Physical magic tended to expend less energy than mental magic, and Loki was sure that with his guidance, Harry would have enough to kill the Dursleys.
The only thing stopping Harry from trembling in fear as he entered number four Privet Drive were the reassuring words of Loki echoing through his head.
He attempted to close the door quietly, but Vernon had the ears of a bat where Harry's "mischief" was concerned and was already marching up to him.