Ray MK III (Japanese: Custom Robo - カスタムロボ, kasutamu robo) is the third iteration of the 'Ray' model from the first title in the Custom Robo series. It is a well balanced 'Jumper Model' from the shining fighter line. Its minimal reliance on customization makes it an ideal robot for beginners.
Ray MK III makes an appearance in Brawl as a secret Assist Trophy, unlocked after playing 100 brawls. This small yet hardy fighter leaps around the arena while firing a volley of lasers from its hand-held blaster and occasionally, an explosive charge with his bomb launcher.
- The custom robo used by the main character. It's the latest Shining Fighter model in the Ray line of robots, which appears throughout the Custom Robo series. The main character switches from his beloved Ray Mk II to this model after his sister and father develop it. This one has a great balance between built-in abilities and ease and depth of available customization
- Custom Robo Arena (2006)
Ray MK III makes an appearance as a playable character, but as a Mii Fighter.
- It is very likely, due to trophy description and design of trophy, that this is exactly the same model from the Nintendo DS game Custom Robo Arena, as the player is referred to as the "main" character, and has a father and sister, who created the MK series.
- Lucas and Ness can absorb the green lasers with their PSI Magnet.