After becoming Immortal and the Master of Death during the final battle of Hogwarts, Harry lived for a couple of hundred-thousand years before he decides to put himself to sleep using seals and runes to hide him from people who are looking to use his power for their gain.
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After being beaten up on his birthday Naruto ran deep into the forbidden forest running from the villagers who were making a "Hunt the demon Search" as he tripped over his own feet landing in a lake. Scared and frighten he manages to get up and started running once again not knowing that he had woken up an immortal due to his fear but, was it really his fear and was it a coincidence that he ran right where Harry had sealed himself? Or did the ninetails help plan this all out?