Except for the episode,"Monkey Fist Strikes," when Monkey Fist was with his Valet, Bates, he has continually used his Monkey Ninjas to help him to become some kind of Mythical Monkey Man.
They also fight and battle alongside Monkey Fist, whether they are battling The Yamanouchi Ninja School or Team Possible.
Like their master, Monkey Fist, they are aware that Ron Stoppable of Team Possible also has Mystical Monkey Power.
In "Monkey Ninjas in Space", they found out that Ron Stoppable is the prophesied Ultimate Monkey Master and their leader. For a short period, they were following him everywhere, but the next time that Monkey Fist was seen, they returned to support Monkey Fist instead.
The Monkey Ninjas do not have this power.
At the end Uh-oh Yono after their master is petrified, the Monkey Ninjas scatter away never to be seen again. What becomes of them remains unknown.