The Last Tomb Keeper

The MC is a really poor student that loves playing games.

One of his friends is a popular student detective that convinces him

into helping with a murder case. After viewing the last moments of an old man being held

at gun point, the scene forces the MC into a virtual reality game

dropping him off at a desert landscape with some pyramids.

The MC goes with the flow, and the first thing he sees is a BOSS sand monster

and a quest option. Like any MC, he expects to defeat the Boss to win, right?

No, it turns out he’s the last Gravekeeper and he’s supposed

to protect the treasure against the Tomb Raiders. That old man?

He was his grandfather, and they meet in virtual reality.