The Attack (Animorphs #26‪)‬

The Animorphs have met the Ellimist. He helped to save the kids when they were about to be eaten by a Taxxon. He helpedto free two Hork-Bajir and restored Tobias's morphing ability. But even though the Ellimist has enormous power, he is not allpowerful.He has an enemy. The Crayak.The Crayak and the Ellimist have decided that a battle is necessary to prove their ultimate power. But they don't intend to fighteach other. The Ellimist will choose the Animorphs and Erek the Chee as his champions; the Crayak will choose his own army. Ifthe Animorphs lose, they'll be erased from the universe altogether. And without any Animorphs, there'll be no one left to fight theYeerks...