The Answer (Animorphs #53)

The battle is still raging, and it’s out-and-out war. Jake, the other Animorphs, and Ax have found a way to slow the Yeerks down, but now the Yeerks have decided the best way to win is to just destroy everything and everyone who gets in their way. Just when things look more than hopeless, Jake and the others discover help where they least expected: Taxxons. Creatures so foul and heartless it’s almost hard to believe that they are capable of having any feelings. But Jake and the others soon discover that the Taxxon resistance has its own problems with the Yeerks. And, for once, it looks like Earth may have a chance.