Neyo was a Commander in the Clone Wars, serving for the Republic Forces. Like all the Clonetroopers, he was a clone of Jango Fett. Fett worked for the enemy, but the Jedi saw this as no problem. This mistake would cost them dearly when Chancellor Palpatine issued Order 66, and the Clones all turned on the Jedi.
Neyo was in charge of the 91st Reconnaissance Corps.