I just managed to get the God achievement alongside the mechanical one - they are both related to the alternative ending, I won't spoil much, but just like the gallery tells you, it's related to the robot events; you have to get the robot all what she needs, then you have to have her in your party alongside with portal creator, obviously requiring you to escort both of them, because the enemies in those portals are much stronger than each of them individually. That's not telling about the battle that goes after, but it should be a hint to what awaits then.
Anyway, the God achievement gives a trait that unlocks hidden potentials of the 3 protagonists, giving them each a unique skill, while mechanical unlocks 2 things - a profession related to make robots, and a trait that works similar to anomaly trait; it gives a chance for robots to spawn instead of normal creatures, and all of them are fairly powerful, like the 2 point divine favor special units.
Now I wonder what's next after literally defeating the "creators"...