Auron becomes Yuna's guardian per Braska's request. Yuna is thrilled to have him as a guardian, since he is the "legendary guardian" who survived the encounter with Sin. Older and wiser than the rest of the party, Auron knows what they will discover along the way. Nothing ever seems to faze him, since he has a good grip of the world around him.

As an unsent, Auron remains in Spira because he made promises to both Jecht and Braska. While Braska cannot be there for Yuna, Auron is there, providing her with support and his knowledge. Auron is the one to point out that Yuna is "easy to read," saying that she is naïve, "serious to a fault," and extremely independent, hating to ask others for help. (Ironically, she has six guardians, but she considers them friends, not simply guardians.)

Yuna is very grateful for Auron's presence as a guardian. She is very thankful that he went all the way to see Kimahri, who then went on his instructions to find Yuna and take her to Besaid. "Having you as a guardian was so great an honor that I don't know how to thank you." No doubt Auron was her most resourceful and useful guardian. In the end, Yuna is able to let him rest, defeating Sin permanently and then sending him.

Auron: Lost your nerve?
Yuna: No. Nothing frightens me now.
Auron: Braska would be proud.
Yuna: Then ... I must not let him down.

Auron is concerned about Yuna's well-being. Though he doesn't really show it, preferring to stay stoic and silent, he does watch over her and Tidus. He is the stand-in father figure, and truly looks out for them. He wants Yuna to succeed and tests her strength, but he has faith in her. Auron is one of the voices that appears in the final battles of FFX-2, pushing Yuna to keep going.