These quasi-living constructs are in the shape of ponies, but are not of the ponykind.
Ability Score Increase: Your Constitution score increases by 2. Your Intelligence increases by 1.
Age: Steelhearts take an extremely long time to be constructed and then to mature. After two years of effort bringing one into the world, they are only considered adults after at least half a century. They live for seemingly forever, watching centuries pass by without effect until upwards of half a millennia.
Alignment: Their selfish natures lend them an evil tendency as they are out to win, at any cost.
Size: Your size is Medium.
Speed: Your base walking speed is 50 feet.
Conductive: You have resistance to lightning damage.
Fingerless: Like the ponykind they resemble, Steelhearts may use their mouth as one hand and are considered small sized for sake of what they can wield or not.
Four-Legged: Being a four legged creature, you can bear greater weights (50%) than a human of the same Strength without being encumbered. Any roll to avoid becoming prone is made with advantage.
Languages: You speak, read, and write Common.
Living Construct: Even though you were constructed, you are a living creature. You are immune to disease. You do not need to eat or breathe, but you can ingest food and drink if you wish. Instead of sleeping, you enter an inactive state for 4 hours each day. You do not dream in this state; you are fully aware of your surroundings and notice approaching enemies and other events as normal.