Warforged

Warforged are sentient constructs, artificial humanoids, created by House Cannith in 965 YK to be soldiers in the Last War. They are sentient and have free will, which earned them the same rights as other citizens of the Five Nations in 996 YK under the Treaty of Thronehold.
Most warforged adopt the culture of the area they live in now that the war is over. They might even dress like their neighbours and try to emulate their speech patterns to fit in. Some of them take such efforts to the extreme, even exploring things like eating or sleeping. Others deny their living nature and instead celebrate the thinks that differentiate them from organic humanoids.
Warforged are magical in nature and don't tire in the same way that humans do. This makes them exceptional manual labourers, and as you would expect, soldiers. They also don't need to eat or sleep, and only desire shelter, something that has been used by some companies to exploit the warforged and justify paying them less than they deserve.
House Cannith kept talk of a religion to a minimum when training the Warforged, outside of what they needed to know to potentially prepare them to fight clerics or paladins. With it being uncertain if Warforged even have souls, they were taught that destruction meant oblivion and that clerics and paladins were just spellcasters, like wizards. In the years since the end of the war, many warforged have really encountered religion for the first time. Most of them don't understand why someone would worship a deity, it seems very much like choosing a master who never gives commands. Those warforged who have adopted a religion have likely done so wholly, they weren't brought up with the idea and so any religious warforged has made a conscious, deliberate decision to believe.
There is an unanswered question of whether or not the warforged possess souls. It was intensely debated during the Thronehold Accords, with House Cannith arguing that they did not, because how could House Cannith create souls? Breland was the strongest supporter of warforged rights, the King Boranel argued that they must have souls, as they can be resurrected using divine magic. In the end, the question of whether or not warforged has souls was left unanswered. They were freed and given rights because they exhibit thought and free will, they are sentient creatures.

Genetic Descendants

• Warforged Juggernaut