The Thunder Stallion was originally planned as a totem 'Mech, along the lines of the Mandrill or Fire Scorpion. Upon learning of the less-than-ideal performance of those 'Mechs, Clan Hell's Horses de-emphasized the totem aspect in favor of more combat effectiveness; only the back legs of the 'Mech still suggest the original equine styling. Despite the changes in design emphasis, however, Hell's Horses MechWarriors still dislike this 'Mech. The Thunder Stallion epitomizes support, in keeping with the Horses' preference for placing infantry and conventional forces on a more even footing with MechWarriors. The Thunder Stallion works so well supporting non-'Mech forces that MechWarriors assigned to it feel humiliated in comparison to their colleagues in other Clans where MechWarriors dominate.

Designed for support, the Thunder Stallion has a standard 255-rated fusion plant that allows it to move just fast enough to keep up with dismounted Elementals and other support units. To make up for its lack of speed, the 'Mech mounts two paired LRM-15 launchers in each side torso, with enough ammunition to allow almost three minutes of continuous firing. Working together with spotter units, the Thunder Stallion can saturate enemy installations and units from the safety of covering terrain.
As a secondary weapons system, the Stallion mounts a massive LB-20X autocannon for close-in work. Usually employed against armor or infantry units, this weapon typically carries a ton each of cluster and standard rounds. in case the warrior should need a heavy punch against a larger opponent. Unfortunately, the arrangement of this weapon and its ammunition stores is of great concern to Stallion pilots. With internal room at a premium, the designers of the Thunder Stallion chose to run the ammo feeds for the massive gun through the 'Mech’s head, just beneath the cockpit assembly, and the central torso section. Should either of these locations suffer a breach while still loaded with even a single round, death for both ’Mech and warrior is practically guaranteed. Though the ’Mech's heavy armor makes such explosion a rare event, many Stallion pilots refuse to reload the autocannon. preferring to risk getting caught without their largest gun rather than die ignominiously in this "quad coffin."

The Thunder Stallion is unique to the Hell's Horses Clan, and is deployed fairly evenly throughout all Horse Galaxies. The greatest number of these 'Mechs, however, appear in Eta and Iota Galaxies.