Lirem-Arrepath-Terrouss is a stern veteran Andalite Prince and head of the Andalite council. He served in many battles, including the Yeerk invasion of the Hork-Bajir homeworld where he was an advisor to the Hork-Bajir. When he learned that Elfangor broke the law of Seerow's Kindness and gave the morphing power to five alien youths, he orders Ax to assume all the responsibility for Elfangor's action to preserve his honor. Ax reluctantly complies and is consequently forgiven. Lirem understood going above the law to help brave people fight the Yeerks, such as the Hork-Bajir, but they were not Andalites. But even those they lost, he would not break Andalite laws, he orders Ax to do the same.
When Ax contact the Andalite homeworld one last time to deliver a message from Alloran-Semitur-Corrass, he says that Earth is now his home and that he will tell the Animorphs everything, he won't let the humans be destroyed like the Hork-Bajir, which angered Lirem and him says that Ax is just like his brother.