MTL - Legendary FBI Detective - Chapter 3 I'm self-defense

One of the seven strongest people on the continent, the King of Mercenaries. He started a war to avenge his fallen family and destroyed territory but failed and lost his life. However… “Wow, I’m alive?” I returned to the past, back through time. A perfect opportunity to right my regrets and reverse everything. It doesn’t matter if people around me point fingers, calling me a scoundrel, or dismiss me as tr*sh. Because… “I’ve got a plan.” “What plan?” “A plan to destroy everything.” There won’t be a second failure. This time, I’ll wipe out all my enemies. …But first, I need to rebuild this damn estate.

Xue Xi is forced to fall in love at first sight with this dangerous man on their first meeting. With death being the only other option, she makes the first move:

Qin Guan was reborn and sent back to his final semester in High School 18 years ago. Getting a second chance at life, he works hard to turn things around and eventually become a Prince Charming. What will his life be like the second time around? What will he have to go through? How will he succeed in turning from a loser into a Prince Charming?

The universe is big, and Hayden’s about to invade it. Being drafted into a demon army wasn’t on Hayden’s bucket list. But when his soul is shoved into a human soldier on the eve of a new invasion, it’s not exactly like he can appeal the decision. Surrounding Hayden are demons, excited and ready. For them, the invasion promises a feast of souls and new growth. Their target? Berlis — a sword and sorcery realm straight out of classic fantasy. Hayden’s human status puts him at the bottom of the totem pole, meant to be cannon fodder that soaks up damage and dies first. But as he plunges into the carnage, he’s learning that he was born for the madness. Readers can expect: + Grimdark action and violence + Fighting, lots of it + Multiple worlds and magic systems + Slow burn