He bears much resemblance to Suppaman (Kuraaku Kenta) from Dr. Slump (one of Akira Toriyama's previous manga). Onio is enraged, causing him to become a Super Saiyan, when Neko Majin Z touches his wife's breasts, but quickly loses in a fight scene.
Like all the Saiyans, his name is based on a vegetable, which is in this case an "onion."
Onio made his first appearance with his wife Honey in "Neko Majin Z," where he comes to Earth looking to make the planet his summer home. Neko Majin Z thinks they are tourists and goes to them dressed up as a Koala. Neko Majin Z's friend (a boy with no name) asks them if they want a photo so they can show off. When the boy takes the photo Neko Majin Z casually fondled Honey's giant breasts. This made Onio really angry and caused him to transform into a Super Saiyan. Onio then kicks Neko Majin Z away, but Neko Majin Z comes back and a battle begins. Neko Majin Z then uses his own type of Super Saiyan transformation and makes quick work of Onio. Honey then drags Onio into their ship and they fly away.
The next appearance of Onio is in "Neko Majin Z 2," where he comes to Earth with Lord Kuriza for revenge. When Onio arrives he finds Neko Majin Z, who is starting a match with Thunderbolt. Onio's interruption causes Neko Majin Z to become angry and he ends up kicking Kuriza into the ground, even finding oil this way. After Kuriza transforms, he gives up, and Onio and Kuriza stay with Neko Majin Z until they can fight again (they never fought again).
Onio also appears in "Neko Majin Z 3," where he is playing soccer with Kuriza, Neko Majin Z, and the boy with no name. The manga begins with them playing soccer, with Onio kicking the ball to Kuriza who kicks it up in the sky. When Neko Majin Z and Onio go to get it, and Neko Majin Z hits the ball, they see a space pod. The space pod belongs to Vegeta, who had been sent to look for Kuriza and Onio by Frieza's orders. Onio says that they are on the planet because there is one outrageously strong guy, Neko Majin Z. Vegeta begins to fight Neko Majin Z but loses and goes Super Saiyan. Onio says that he also went Super Saiyan but it was no use against Neko Majin Z. Then Vegeta pretends he has a phone call and leaves, claiming that "he will never appear in a gag manga ever again." Kuriza asks if a cellphone can reach a planet like Earth, to which Onio answers that it is out of range.
Even though he can become a Super Saiyan, Onio is not very strong, as even as a Super Saiyan he is said to be weaker than First Form Kuriza and base Vegeta.
Techniques and special abilities
- Flight – The ability to fly with the use of ki.
- Energy Wave – The most basic form of Ki Blasts. Used to showcase his power after his Super Saiyan transformation.
- Full Power Energy Wave – Used against Neko Majin Z when the latter transforms into a Super Neko Majin. Onio fires this technique in a fashion similar to Dodoria's Maximum Buster.
Onio is able to transform into a Super Saiyan. It was first displayed by him during his battle against Neko Majin Z.
- A Saiyan with a physique similar Onio appears in Dodoria's flashback of the Saiyan race in Dragon Ball Z.