- "Because you're the same, you and Polo. He's you, and you're him. The leaders. You know, he took a risk putting down his spear. We might have killed him and his people. There was no way he could know if it was the right thing to do. He just made the best decision he could. That's all anyone can ask from any leader."
- ―Cassie to Jake
Polo met the Animorphs shortly after they demorphed from their monkey morphs. 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 diabos, 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. After 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, although Jake was then killed by the Visser. Because the entire event took place in a Sario Rip, an alternate timeline, Jake's death caused his consciousness to be sent back to his body in the past, and with the foreknowledge in place, caused Jake to cease the timeline from ever coming to fruition.