To the approximately four foot robot, that's more than tall enough for something called a monster. Surely it would scare most humans and other organic people. Link's use of a sword to demonstrate also leaves quite the impression. Atom gets a good look at the sword, and his visual scan notes the signs of age and wear, as well as tending.

"Oh wow..." Atom gapes for a moment. A monster slayer with a sword? "Are you some kind of knight or warrior back home?"