Andro Umeda is an extraterrestrial being and a central ally in the Space Knights. He is the sole survivor of the planet Sanno, his homeworld and all its inhabitants having been destroyed by the Waldasters, the primary alien antagonists of the series. His name is derived from the Andromeda galaxy, which he also uses as an alias while living on Earth. Rescued from a Waldaster attack by Dr. Amachi, the head of Earth's defense organization, Andro was recruited to join the Space Knights, lending his unique extraterrestrial abilities to the cause of protecting Earth.

Andro possesses a human-like appearance resembling a person of Latin-American descent, most notably characterized by a large blonde afro. This form is actually a disguise he uses to blend into human society; his true appearance as a native of Sanno is said to be different from a human. His personality is marked by irreverence and a confident, sometimes arrogant, demeanor that stems from his superior alien knowledge and psychic powers. This attitude often puts him at odds with the hot-headed protagonist, Johji Minami (Tekkaman). Johji, driven by a personal vendetta against the Waldasters for the death of his father, is initially suspicious of all aliens and frequently labels Andro a potential traitor. Despite this friction and Johji's distrust, Andro remains non-hostile, as their shared hatred for the Waldasters serves as a common drive that allows them to work together.

Initially, Andro's motivation for fighting alongside the Earth forces is purely for personal vengeance against the Waldasters for the annihilation of his people. His primary goal is to obtain a Waldaster spaceship to return to what remains of his home planet. However, over the course of the series, he begins to mellow as a friendship develops with Johji Minami. He comes to trust the people of Earth, ultimately choosing to gamble his life and the future of his own planet Sanno on Johji and the Earth's defense. He operates alongside his comrades on the spacecraft Blue Earth, which include Johji Minami, the pilot Hiromi Amachi, and a fellow Sanno native, a small, intelligent mutant creature named Mutan.

As an alien, Andro possesses a bundle of knowledge about space and other races. His most notable abilities are his potent psychic powers, which are on par with the Waldasters' elite Space Ninjas. These powers allow him to perform incredible feats. He can transform into a form described as a ball of blue light, which lets him move at lightspeed, phase through solid walls, fly, and teleport. He also possesses superhuman strength far beyond that of a regular human and can disguise his appearance, even taking the form of a Waldaster. His alien physiology allows him to survive in the vacuum of space for brief periods. However, these abilities are not without limit; overusing his powers causes Andro to fall into a state of severe exhaustion, leaving him vulnerable to attacks. His fighting capabilities have been featured in various video game adaptations, such as the fighting game Tatsunoko Fight, where his special moves include Lightning Attack and Teleport.