The dwarves created many magical constructs, but only one—called Mechanica—is sentient. Mechanica are intelligent humanoid creatures made of gears and metal. They have a fire elemental motor inside them (called Heartfire).
Every mechanica has a strict code (programming) that guides them. They fight with themselves every time they act outside this programming. They have emotions, but these feelings confuse and overwhelm them, and they struggle to express them at all.
They are not remorseless or sociopathic, but others can see them that way. In general, humans don’t trust mechanica, since they associate them with their dwarven masters. Dwarves often treat them as tools or machines, not as sentient creatures, and their telepathic orders to them can change their mechanica programming. Elves treat mechanica as enemy weapons, destroying them on sight. Tieflings rarely even notice them, since their souls don’t shine like those of other races.
A mechanica PC has a code of honor that serves as its programming.