Quest is given by Elonca Nusback at the Liberation Squad Camp (-912.01, 117.92, 219.02) in the cave leading to Crushbone Keep.
"In the Cave leading to Crushbone Keep is a small contingent of dwarves preparing to rescue their comrades. One of the liberators, a stout lady named Elonca Nusback, has sought my help in their fight. If I can obtain ten belts from the Crushbone Centurions who patrol the outside of the castle, she will supply me with a belt worthy of my efforts."
10 belts required
The Centurions can be found in the Crushbone Keep area, the centurions inside the castle should also give the update.