Trainer, A.K.A. Experiment 623, is an illegal genetic experiment created by Jumba Jookiba. He is designed to retrain experiments who have lost or forgotten how to carry out their primary functions, and be a master of all combat skills but failed because thou he know all combat skills he only uses judo. His one true place is martial arts acadamy teaching students judo as Kixx's partner in his dojo.
Experiment 623 was the 623rd genetic experiment created by Jumba with Hämsterviel's funding. He was designed to be a master of all combat skills but failed because thou he know all combat skills he only uses judo
623 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.
All of the experiment pods were released and scattered across the island of Kauai.
At an unknown point, 623 was persumbably activated, tamed, and named Trainer.
All 624 experiments, including Trainer, were round up by Leroy and taken to a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben and Gantu arrived before the experiments could be destroyed.
It is unknown whether or not Trainer participated in the following battle between the experiments and the Leroy clones.
The Leroys soon gained the upper hand in the battle, but were defeated when Lilo, Stitch, Reuben and several other experiments performed the song Aloha Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.
Trainer is a slender, tan Stitch-like experiment with green eyes, two stubby antennae with a single ring around each, light brown hair, a white belly and lower jaw, two black-tipped spines on his back and a black, cloth belt around his waist. Trainer is a failed experiment because even though he knows all combat skills he only uses judo.
Trainer was crafted to not only be Jumba's personal trainer in fitness and in martial arts, but also has the ability to retrain Experiments so that they can remember lost functions if such an event occurs. Trainer keeps a karate gi to emphasize his powers, and also tends to keep his eyes shut to keep his mind in zen. However, the strange fact is that while Trainer knows all martial arts, as a key failure to his creation; he only performs judo as a means to protect himself.