Marvel: Start with Level Five Mutants - Chapter 5: Take action and escape

A 13-year-old deaf teenager living in the 21st century suddenly found himself as a young boy in Japan during the early 1900s. With two World Wars, two nuclear bombs, Hitler and many other disasters awaiting his future, he thought things couldn't get worse.Except it did.He found out later on that he had actually reincarnated into the world of Demon Slayer where man-eating demons ruled the night. He thought things couldn't get worse.Except it did.But hey! At least he had unparalleled talent, incredibly special eyes and future knowledge.How will the story of Demon Slayer change with the addition of this unique character? Will so many still die if the Hashiras had one more pillar in the final battle?Or will the story end on a much happier note?

A generation of hegemons, betrayed by betrayal, besieged by forty-nine strong men, tragically killed and robbed the mountain, re-lived once, he will re-enter the peak; strong rise, into the chaotic star field, exhausted 100,000 strong, Wusheng dead and kill, The impact is high!

- Description from 69shu translation

The world had started doomsday, and I struggled for a year, before I died under an enchanted beast’s claw. Heaven has given me another chance, back a day before the end happen. Will I be able to change my fate, and that of my loved ones? Now, I will start my journey on becoming the strongest on the planet that the Gods have changed into a game world.

Kein Rosenguard, a reincarnated girl who suddenly became the crown princess's personal knight!

She fulfills her duties at the side of her highness, Princess Rosarie von Goldheart. A rebellious princess who would rather live her life as dressing as a commoner than attending fancy balls in the castle.

Kein decided she would spend her whole life protecting her Royal Highness but will she succeed in her mission and set aside her growing feelings for her?

Art is not mine! Only the story! Please tell me if you know the artist so I can credit them!