YSS Elfin Princess, NG-X1-392, was a Plumeria-class (2D) Medium Gunship built at Gemini Star Fortress by Ketsurui Fleet Yards in YE 29 for the Star Army of Yamatai's First Expeditionary Fleet. Its name both was a reference to its captain, Taisa Hanako (a princess of the Ketsurui Clan), and to the mythical grace, beauty, speed, and combat ability of Elves in general. It was one of five test vessels based on the prototype YSS Plumeria.

The Elfin Princess had a short career that consisted charting of 20 HX Series Star Systems, a victory at Jun, and then its destruction by Sfrarabla Mishhuvurthyar Xhrafuklurp (SMX) forces. It was replaced by the YSS Eucharis.

Crew members included Ketsurui Sora and Hasegawa Sumaru.