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Kim Yunhi (Korean: 김윤희, Gim Yun-hui/Japanese: キム・ユニ, Kimu Yuni), known as Wraith (Korean: 망령, Manglyeong/Japanese: レイス, Reisu) is a secret agent from Mithril working for the Intelligence division. A master of disguise, she's been assigned to protect Kaname Chidori, as a backup bodyguard to Sousuke. Near the end of Full Metal Panic! The Second Raid, it's revealed she's actually a woman. The light novels mention she's from North Korea and has been in Russia for some time. Her true name is unknown.

An North Korean ex-spy, who is also a master of disguise. As a member of the Intelligence Department, she was ordered to watch Kaname Chidori and protect her from serious threats. Although appearing cold at first, following her 'rescue' by Kaname Chidori from Leonard Testarossa, she has opened up slightly and secretly meets with Chidori. She also saved Sousuke and Tokiwa's lives from Amalgam members on the Jindai High School rooftop and aided in the defusing of the bomb planted on Tokiwa.  She even went as far to perform emergency surgery on Tokiwa after a piece of shrapnel embedded itself inside her diaphragm and then took her to the hospital. Showing further compassion, she also allowed Kaname Chidori to give herself up to Leonard so Sousuke's life would be spared, despite violating her orders. After the events in Continue On My Own, she is still helping Mithril, helping Gavin Hunter to complete the construction of ARX-8 Laevatein at the end of the novel 'Burning One Man Force', and has actually helped to transport the completed Laevatein to Sousuke in the progress of Get Together and Make My Day.