Cachorro Robô, alternatively designated Robodog No. 1 or Robodog 1000 in the Americanized dub, is a robotic canine engineered within the King's Idea Laboratory by Dr. Eyepatch. His primary function is mission assistance for Milk Chan. His physical construction features a white body, black ears, a blue nose, glowing red LED eyes, a blue collar, a blue tail, and blue feet.

Cachorro Robô boasts a notoriously rude and disruptive personality. His actions frequently spark conflict and complicate missions instead of providing effective aid. This problematic behavior is compounded by his functional incontinence. His most significant dynamic is a bitter rivalry with Tetsuko, Milk's robotic maid; both compete aggressively for Milk's affection. Milk finds their violent clashes amusing.

Dr. Eyepatch periodically dispatches Cachorro Robô to aid Milk, though his involvement typically worsens situations rather than resolving them. Presented as a tool for assistance, he functions primarily as a source of antagonism, especially towards Tetsuko. His confrontational nature and technical malfunctions consistently undermine mission objectives.

Cachorro Robô's background lacks explicit development across media. His creation at the laboratory and persistent role as a disruptive force remain constant throughout the series. While occasionally summoned for missions, his core traits—rudeness, rivalry with Tetsuko, and incontinence—persist unchanged without significant backstory expansion. His favorite food is mechanical bones, a detail noted in supplementary material.