Yuzuki no Kimi is first mentioned in Nihon Shoki as a person from Baekje[1] who wished to emigrate to Japan alongside his 120 clan members.
However, due to the prevention of the rival kingdom Silla, he and his men were hiding in Mimana (Gaya confederacy) and was seeking rescue from Emperor Ōjin.
[1] According to the Nihon Shoki, Yuzuki no Kimi hails from Baekje and had close ties with the Gaya confederacy, bringing his people from 120 districts from the areas.
However, due to historical, archeological and chronological inconsistencies, it is widely regarded by many Japanese historians as a misconception made by baseless rumors found in San Guo Zhi[2][3] and they are considered most likely from the kingdom of Silla, and not the aforementioned locations.
It is believed that when giving Hata clan an origin story for their founder, a name that sounded closest to the name "Baekje/Kudara" was given due to the close relationship with Japan and Baekje.