The Immortal Emperor Returns - Chapter 601 - Those Not Belonging to My Race Is Unworthy of My Trust!

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

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

In a world where power reigns supreme, Zoey Monroe was born with nothing. Labeled “Mana-less” in a society of Hunters, she was the stain on the prestigious Monroe Family, a shame to one of Sunrow City's most powerful bloodlines. Ridiculed, ostracized, and treated as less than human, Zoey endured years of scorn.Until one day, at seventeen, she made a choice—to leave it all behind.Six months later, struggling to make ends meet in the city, Zoey’s life takes an unexpected turn. After another grueling day at work, she returns home, only to witness a dungeon rift tearing open behind her apartment.Drawn by curiosity—and the desperate hunger for change—she steps inside. But the dungeon is merciless. Death looms over her, suffocating, inevitable... until—[Enough Mana Has Been Accumulated!][Error! A mysterious system has already been bound to the host. Adjusting...][Ding! Installing the A Hundred Times System!]In an instant, Zoey's fate is rewritten. From outcast to overpowered, from weakling to warrior—the path to greatness has begun.This is her story.

One week. If you survive, you choose a Cosmic Power... you survive. Jace isn’t one to give up. Not when his sister dies. Not when he loses his legs. And definitely not when The Cosmic System takes over Earth. With nothing more than his street smarts, the clothes on his back, and a river otter companion; he must survive a planet full of vicious predators that see him as an easy meal. If he can survive? He gets to choose a Cosmic Power and a Class. A path to ascension. A way to bring his sister back.