MTL - Into Unscientific - Chapter 487 This is Yongling (nine thousand characters)

“What kind of guardian would you want to be? the one who destroys everything or the one who protects everything?”

Jason, one of the many casualties during a nuclear explosion gets the chance to reincarnate into another world due to his deeds during the war.

He gets tossed to another world due to ending up with the Shadow god as his patron, something deemed impossible.

With a system to guide him in the world of Clover and a family jinxed through the generations, his adventurous life in new world begin.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

The hidden dragon stirred from its sleep, the fierce tiger descended the mountain! Ye Wudao, following his master's orders, crossed into the mortal world, his medical skills so advanced they could reverse fate, his divine magic alone dominating the universe. Whoever dared touch my dragon scales, regardless of their power or status, was met with instant death!

I am the most talented guardian of this era!

But no one knows, I still have a second template, the knife cuts the flesh, the intention cuts the soul!

You may have seen the meatless juggernaut, but you have never seen a full-time meat shield with an explosive attack!

- Description from novelbuddy