This is The Silver Guardian (銀之守墓人, 銀の墓守り), a Chinese web manhua by Ling Meng and Ming Xung.
The main character, Shu Yin, is wearing a red scarf in almost all scenes I have seen.
In Chapter 2, Page 3 there is a scene where an older man is speaking to what appears to be a young Shu Yin and he says:
So are you interested in grandpa's new video game idea?
And again in Chapter 5, Page 2 an elderly man appears out from a tomb and says:
My dear grandchild
Do you like what your grandpa has prepared for you?
More scenes from when Shu Yin was a child talking to his grandfather are from Chapter 8, Page 6 - 9, where his grandfather accidentally rips the scarf and offers feathers to Shu Yin for it to be mended.
And finally in Chapter 8, Page 12 there is a scene where Shu Yin's scarf activates and he flies off.
The description alludes to the fact he is the last Gravekeeper, and keeping the treasure safe from raiders:
...he expects to defeat the boss enemy to win, right? Alas, it turns out he's the last Gravekeeper and he's supposed to protect the treasure against the Tomb Raiders.
The summary has the following points:
Shu Yin is a poor gamer whose consciousness goes to a virtual reality game without warning
His quest is not fighting monsters, but to help them protect treasures from players called Tomb Raiders
A story of a gamer's purpose to protect the tomb from raiders that want to use the power within it