Perhaps the creatures are central figures in a now-obscure Sylean religious sect (which if the applicable records had survived the Long Night would turn out to be a syncretism of Solomani Christmas traditions with Vilani ancestor worship). Every year, hunters trap them in the high mountain preserves on Sylea and Rare Exports ships them out to Sylean recreationists scattered across the Empire. When the chartered vessel headed into the campaign area breaks down, the PCs are contracted to complete delivery of the cargo. This is a good excuse for the party to visit all the important worlds in the campaign area. And - of course - at some point along the way the low-berth containers transporting the creatures break down and the cargo undergoes automatic emergency revival. Given their innate hardiness, most of the creatures successfully revive. Much to the party's distress . . .