Sinjir Rath Velus is a human former Imperial loyalty officer from Sevenmoon, introduced in Chuck Wendig's Aftermath (Del Rey, 2015). His Imperial job was interrogating and punishing his own side — the officer the Imperial Security Bureau sends when a unit's morale is suspect.
Deserting
He walks away after Endor, drinks his way across the Outer Rim, and falls in with Norra Wexley's team on Akiva more or less by accident. The Aftermath trilogy uses him as its comic voice and its most uncomfortable one: he is very funny, very good at reading people, and both of those are professional skills he acquired doing something unforgivable.
Useful to the winners
His interrogation technique turns out to be exactly what the New Republic needs for hunting Imperial war criminals, which the books treat as a genuine moral problem rather than a joke. Chancellor Mon Mothma eventually appoints him a political advisor, and he is instrumental in exposing the syndicate pressure on senators that was blocking intervention at Jakku.
Afterwards
Two years after Jakku he marries the slicer Conder Kyl and stays on as Mothma's advisor through the Military Disarmament Act — the decision that leaves the New Republic unable to answer the First Order thirty years later. Sinjir is on the winning side of an argument that the sequel trilogy proves was wrong, which is an unusually sophisticated place to leave a comic-relief character.
