Mr. R3 is Naoko's robotic teacher.
Mr. R3's head has what's designed to be a black shaven top and thick black eyebrows. His body is square-shaped with a violet downturned triangle, a red capital R in the center, and the rest of his body is colored lavender. His limbs are noticeably ball jointed.
Mr. R3 speaks and acts in a stereotypical robotic fashion and manner.