Valkyrie's Shadow - Chapter 9Before the Storm: Act 6,

Do you know how this world ends?

Traveling to the wizarding world, Eli found that he was an Eternal.

Life is infinite, life is immortal.

“What? The talent is very poor, then I will meditate for ten years, centuries, and thousands of years, and I can always meet the promotion requirements.”

“This skill is hard? Oh, let me study it for decades to see if it’s really that hard?”

“Consuming life force, improving mental force, and this kind of good thing.”

“The enemy is here? Oh, let me find a place to hide for a thousand years, until his lifespan is exhausted and his mental power dissipates, and then I will come out again, free and endless void.”

…

This is the story of an immortal who lives in the wizarding world and then kills the endless world.

- Description from novelbuddy

Meet Sora and Shiro, a brother and sister who are loser shut-ins by normal standards. But these siblings don’t play by the rules of the “crappy game” that is average society. In the world of gaming, this genius pair reigns supreme, their invincible avatar so famous that it’s the stuff of urban legend. So when a young boy calling himself God summons the siblings to a fantastic alternate world where war is forbidden and all conflicts–even those involving national borders–are decided by the outcome of games, Sora and Shiro have pretty much hit the jackpot. But they soon learn that in this world, humanity, cornered and outnumbered by other species, survives within the confines of one city. Will Sora and Shiro, two failures at life, turn out to be the saviors of mankind? Let the games begin…