Diego is a saber-toothed cat found in all five of the films. He is Shira's love interest. He has a sardonic personality, although it is not intended to be nasty. He was sent by his pack to retrieve the human baby called Roshan; When he found Roshan in Manny and Sid's care, he pretended to lead them to the humans, but instead planned to lead them into an ambush by the pack. However, when Manny saved his life, Diego had a change of heart, confessing about the pack and sacrifices himself to help them escape. He was seemingly killed by the pack's leader, Soto, but survived and joined Manny and Sid on their travels. In the second film, he was revealed to suffer from aquaphobia, but he eventually conquered it in order to save Sid, Crash and Eddie. In the third film, he began to fear that he was losing his predatory abilities from being in the "herd" too long, and considered staying in the underground dinosaur world with Buck. He changed his mind after managing to save the labored Ellie from a dinosaur attack. In Ice Age: Continental Drift, another Smilodon named Shira joins the group, and Diego feels attracted to her. During the end credits, Diego and Shira are seen nuzzling each other showing that they have now become a couple. In Ice Age Collusion Course in the lives in woods with shira in the southern tip of Illinois near in the future Chicago.