The Kelbrid are a fierce race of aliens who live in a section of space known to the Andalites as Kelbrid Space, having made a treaty stating that neither of them can cross the border. Interestingly enough, the Andalites have never seen the Kelbrid themselves, and their appearance is thus not known. After the Yeerks lost the war on Earth, Tom's group of rebels fled into Kelbrid Space, trusting that the Andalites and their human allies would not follow. However, the Animorphs disguised themselves as criminals so they could chase after them without reprecussions. During the exploration of Kelbrid Space, the Animorphs saw no signs of Kelbrid activity, as the sector was oddly empty of any signs of intelligent life. Its possible the The One was a Kelbrid, but this can't be confirmed.