MTL - Warhammer: The Beginning is the Crisis of Annihilation - Chapter 351 Start a war with reincarnation games (subscription required)

Zane was just a working-class adult with a passion for one thing—Cursed Bloodline Online, the once-revolutionary game that had faded into obscurity. After six long years of grinding, he was finally on the verge of ascension—until everything changed.His bloodline suddenly reset.The world itself changed immediately after.And without warning, everyone between the ages of sixteen to thirty vanished—pulled into the game’s world.Now trapped in the Realm of Bloodlines, Zane finds himself different from the others. While most awaken standard paths to power, he inherits a hidden Bloodline Class—the Cursed Bloodline of the Vampire Progenitor, the same bloodline that mysteriously appeared on his account just moments before the transfer.Alone, hunted, and feared as one of the last of a forgotten, despised race, Zane must fight to survive. To grow stronger before the world turns on him. To uncover the secrets of his cursed identity. And to discover what force brought them all into this deadly game.Slowly but surely, he forgets himself from the past, overtaken by the life of the body he now inhabits and the mysteries that surround it, becoming the very thing that caused the gods to curse his race in the first place.

A boy wakes up with omnitrix as a X-GENE

Hiding in the Cold Palace and eventually becoming a Boss of Sorts. Li Mu was transported to a fantastical world and became a measly eunuch of the State of Xia. Despite having initially thought that his life would be a miserable one, he had unexpectedly acquired a check-in system.

At first, when he learned that he was forced to go to many different routine worlds and be reborn into all kinds of cannon fodder, he was against it.