Isekai Omnitrix: Book 1, The Ressurection Of a Hero.

When 19-year-old firefighting prodigy, Ryan, dies in the line of duty, he expects his time on earth to be over. But in a twist of fate, his soul is chosen for reincarnation, and he's given a chance to resurrect in a world where the characters of Ben 10, High school DxD, MHA, Dragon ball, and Re: zero are all real.

But there's a catch - he finds himself in the body of a young Ben Tennyson, with all the challenges and responsibilities that come with it. With the Omnitrix at his disposal, he must navigate this new reality, with the fate of multiple civilizations hanging in the balance.

But with twists and turns at every corner, his new life is far from certain. Can he trust those around him? And will his Omnitrix and newfound allies be enough to save him from the darkness that lurks ahead?