From Destinypedia, the Destiny wiki
Yuna is an Exotics Vendor located at the Tower, in the Bazaar near Ikora and Hawthorne. She currently serves as an exotics vendor for the Mugunghwa Legion, with a rotating inventory of exotic arms and armor.
Special Vendor Status
Available exclusively on the Asian servers, use of her services requires one to be an "IGR Benefactor" (Internet Gaming Room) which is exclusive to gaming and e-cafe's in South Korea. The exotic items she sells, however, are also available during Baron Strikes and missions, and are not exclusive to her as a vendor, or exclusive to the South Korean region.
"Nice to meet you. I'm the official Mugunghwa Legion Merchant."
"I'm here to bring you exceptional wares to thank you for your participation in Mugunghwa."
"You're a special group of guardians, and I hope to see you often!"
Yuna has a gift for you on behalf of the Mugunghwa Legion. She hopes you will return as a member of the Mugunghwa.