One Piece: Unreal Adventure - Chapter 84: Sometimes it was honestly good being a hero.

[Congratulations, Host! You have transmigrated to a magical world.]Good![Congratulations, Host! You have received a transmigration gift: SSS-tier identity—Prince of Ilan!]Very Good![Congratulations, Host! You have received a transmigration gift: SSS-tier Gift—Marty Bloodline!][Level-up Speed ×10, All Spell Power ×10]Very Very Good![Generating Bloodline…][0%... 5%... 35%... 42%...]Can’t wait any longer~~~[Warning! Warning! Warning!][World backlash detected! System is about to collapse!][Host, please evade! Host, please evade!]Wait, are you kidding me???[Bang!]And just like that, you transmigrated into a magical world.With the system gone, despite your extraordinary talent, you chose to lay low and survive.The world is vast, but staying alive is the top priority.Years later, a rumor began to spread around you:“Wait… you're telling me that useless prince… has been god rank all along???”

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

This is the story of a modern sailor who was accidentally reborn as a soldier of the Brazilian Expeditionary Force, and finally became the largest plutocratic family in Brazil by virtue of his foresight.

- Description from novelbuddy

When the goddamn story leaves you no choice but to walk the path of the villain,The heroes aren't enough to save the world, as the calamity ultimately kills everyone and everything.Then, only by becoming the demon king can you survive, and only the demon king can save the world, but how?Of course, by conquering every other race, obviously.Can Axel become the demon king and survive, maybe save the world in the process?