Polo is a South American native who was allied with the Animorphs in the events of The Forgotten. He led a group of at least twelve other men in his clan.
Polo met the Animorphs shortly after they demorphed from their monkey morphs at about 5:25 PM. Because of this, he believed they were monkey spirits, as translated by Marco. Despite speaking different languages, Polo and Jake were able to understand that they shared a common enemy: the diablos, or Hork-Bajir, as well as the other Yeerks that had landed in the rainforest. Before a sudden storm ended their conversation, Polo promised Jake that he would help him hunt the Yeerks.
Later, when the Animorphs were trying to fight off Visser Three at the Blade Ship with the intention of stowing away on it, Polo came through on his promise. He and his men threw spears and downed many Hork-Bajir warriors. Polo himself attempted to hit Visser Three's Lerdethak morph, but a tentacle caught his spear and tossed it back. Later, when Jake had morphed monkey and swung through the monster's tentacles, Polo threw his spear again, this time for Jake to catch. Jake was able to stab the Visser with the poisonous weapon before he was strangled and/or swallowed.
It is unknown what happened to Polo after the fight.