Wex was an identity taken by Odo in 2376 in his quest to locate the missing Bajoran Kai, Opaka Sulan. He took the form of a Trelian female and tracked down Opaka Sulan on the planet Ee. Odo then travelled with Opaka and Jake Sisko to the Idran system and then the Alpha Quadrant. (DS9 novels: Rising Son & Unity)