The Urch incident was a confrontation that arose out of a Chiss Ascendancy diplomatic mission to the planet Urch, capital of the Urchiv-ki, with whom the Ascendancy had a treaty. The Ascendancy was asked to send Ambassador Boadil'par'gasoi (core name Ilparg) to Urch, and the syndics Mitth'urf'ianico "Thurfian" and Irizi'stal'mustro "Zistalmu" chose Admiral Ar'alani's Nightdragon man-of-war Vigilant to escort the ambassador. The Syndics insisted on sending Senior Captain Mitth'raw'nuruodo "Thrawn" on the mission to prevent him from visiting the Lioaoin Regime as part of his investigations into the conquests of the Nikardun Destiny. However, the invitation was a trap—the Urchiv-ki had been subjugated by the Nikardun, refusing to allow the Chiss to land. Thrawn noticed the presence of a Lioaoin vessel and a Nikardun frigate. In retribution for Thrawn's earlier capture of a Nikardun blockade frigate in the Rapacc system, allied Lioaoi, Urchiv, and Nikardun ships tried to set up a web to ensnare and capture the Vigilant. However, the Vigilant evaded the Urchiv, Lioaoi and Nikardun ships, escaping into hyperspace.
Due to the Lioaoin presence at Urch, Ambassador Ilparg demanded that the Vigilant visit the Lioaoin heartworld for an explanation from the Lioaoin Regime. Upon the Chiss arrival at the heartworld, the Lioaoi denied involvement, while a Nikardun Battle Dreadnought approached the Vigilant. Thrawn identified himself to the Lioaoi, sparking a brief reaction from several Lioaoin gunboats, allowing him to deduce that the Lioaoi were allied with the Nikardun and had standing orders regarding him.
The Urch incident appeared in the 2020 novel Thrawn Ascendancy: Chaos Rising by Timothy Zahn, the first installment in Star Wars: The Ascendancy Trilogy.