Yevan was an Andorian chan or thaan, the eldest son of Thurl, the exiled King of Greater Andoria, born on Pacifica in the late 2350s. He was educated on Earth, where he was exposed to ideas of democracy and governing different from that of his native Andor, and thus, was strongly opposed to the plan to reinstate his father as monarch.
When his father unexpectedly drowned, Yevan insisted on returning to Andor with the body, in ordered to fulfill the traditional Rending Ceremony. During the journey to Andor with Captain Jean-Luc Picard, Yevan came to the decision to claim the throne himself, after which he declared a plebescite to decide on the dismantling of Andor's monarchy. The vote for this proposition was overwhelmingly positive, and Yevan gave up the throne, left Andor, and went into hiding. (TNG - Enterprise Logs short story: "The Captain and the King")