Lore wise: What is an auxiliary?

Is it a robot? A cyborg? A living creature? Or just an entity made of pure photons?

Xiao hacks into yours, so I feel robot. But, this is phantasy! So, could be anything.

They are more than likely androids, and probably the precursors to [Episode 4 Spoilers].

Ah, gets a bit of an ' explanation ' later. Thanks. I don't want to spoil it then.

its a midget slave! >:D

@ZeeHero9271 This answer had me dying from laughter.