Derrick was simply surgical when salvaging corpses, with both his summons unable to look away during the process.
Its hide, muscles, ligaments, bones...
Nearly everything was going into his numerous magical pouches, where Derrick once again saw a fairly decent accumulation of prime materials.
These huge monsters were becoming more and more like treasure chests that would allow him to vastly expand his offerings during the next auction.
If he ever managed to get back there, that is...
Once everything was over, he once again stood next to a huge pile of freshly cut slices of meat, which honestly looked much more appetizing than the troll's.
It had some marbling and its fibers weren't too big, which was a huge factor in determining its chewiness. He really hoped they were as tender as they appeared to be.