who was the...........

Spoilers...

Nirmata was the creator, who created the AI child to take down the human's NOMAD weapon and end the war.

Nirmata also turned out to be the pregnant wife who was assumed killed during the raid early in the film and is later seen in the coma. They cannot switch off her life support to die because AI cannot harm themselves.

Was thinking... it could also be a reference to us, the humans, who are effectively their 'Creator' and some might consider, their 'God'.