Because Leona, the person with the largest Storage Artifact in the entire group, was still unconscious, they couldn't store the Trolls' corpses.
Her Soul Origin was linked to the Storage Artifact, which made it impossible for others to access it.
Fortunately, that was no problem for Zayn. He had countless expanding pouches, which were Pseudo-Artifacts, a Spatial Artifact, which he got from Manager Tilan's body, and the Silvermoon Bracelet.
Zayn had more than enough space to store the three Trolls and the squashed Lesser Earth Dragon.
Even if he couldn't manifest the Spirit of the Lesser Earth Dragon anymore, he could sell the corpse or turn it into a Soul Orb with Glutton's help.
"I will return the Troll corpses when we're at the Silverflame Camp."
