Nine Realms VRMMORPG

A man, no, a hero who fought for his homeland in another world gets sent to a parallel world to be reborn, with his memories intact as a bonus for the extra good karma he had. The thing is, both worlds have VRMMORPGs, and this man used to be the reigning champion on all leaderboards in all VRMMOs he played in. The one VRMMORPG he always played, was Nine Realms.

And now he has the advantage of knowing that VRMMOs base your ingame character on your real world body, and VRMMOs will only come out when he's 10 due to the timelines only differring in political peace.

Time to kick ass.