Anime: Through the multiverse

{Disclaimer}
The MC will not be reincarnated from earth nor will it start with him being reincarnated. I don't plan for the MC to be reincarnated until way later in to the fanfic. He will also be reincarnated multiple times into different universes.
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The story follows our protagonist as he grows and develops in a world where you could be fine one day but then in the next your whole family tree could be annexed. In a world where demons lurk in the darkness. A world where Demon Slayers fight against them.
How will he grow to protect him self? Will he ever be able to?