He lived in Clear Sky Village with his wife, Yesana. He is the biological father of Yunwa, though he would never see her grow up as he died fighting against the Talus Dominion in the Stratus-Talus War.
Before he passed away, he wrote a will to his family of what to do with his family's estate and left it with his friend Chulu, a fellow soldier who went on to become part of the Bokgon Brotherhood following the war. Chulu had hidden the will within the statue of General Gubong in front of Clear Sky Village.
The last will and testament of Muyong is as follows:
"This is the last will and testament of Muyong, scion of the Mu family I feel I must preserve the Legacy of my lineage and make sure that my family's artifacts are no lost forever to time.
If you are reading this, I hope you are of honorable intentions. Mushin's Legacy could be a powerful tool to rid the world of corruption or bury it in it. Because of this, I hope that I have made the right decision.
After much deliberation with the Shadowless, I have entrusted the Golden and Silver Crests to them. The Shadowless, who first guarded Mushin and now guard the Mu family, should take good care of them. Both Unhak of the Shadowless Lotus faction and Gumyung of the Shadowless Orchid faction have been vocal of securing the Golden and Silver Crests before the Talus-Stratus War involves Clear Sky.
The Crests are needed to acquire Mushin's Legacy, and they need to be safeguarded. To claim the Crests, seek out Unhak and Gumyung.
To whoever wishes to find Mushin's Legacy, please use it to bring peace. We need no more wars and corruption."