Scions are a new variation of the HMV developed by The Reclaimers for human use.
Due to the fact that most Xeno technology is incompatible with most human physiology/biology, the allies of the Hydra League was forced to make several changes to their weaponry capable of being handled by human pilots. The Scion was the result. Despite being based off the designs of Decel Erachin, the Scion shares very little in common with it's human-built counterpart.
Despite being developed as closely as possibly for human use, pilots are still required to undergo Biological Augmentation to pilot Scions properly. Failure to do so has resulted in physical and mental trauma.
The Scion first seen service during the raid on Oasis by The Paladins. Despite the failure of the prototypes to prevent Axel Erachin's extraction, the Scions proved to be a success, and are slowly replacing the Hydra League's HMVs.