Okay this is RIGHT before i go to bed but my headcanon is that the pigment for drones get darker. They can also darken from extreme distress and trauma or switch to a different color fully! Also when they’re first activated I think that their colors are always white because they haven’t had a personality (or owner) yet.
N is an example of this (I haven’t been drawing n a lot so he replaced Uzi for this example)










