Lulu and Wakka

Yuna grew up with these two on Besaid. After spending the early years of her life in Bevelle, after her father defeated Sin, Kimahri took Yuna to Besaid. There, she met Wakka and Lulu.

Separated by 5-6 years, the three of them were still able to get along well. As children, they played together with Wakka's younger brother Chappu, and their friendship remained as they grew up. It grew stronger, with Wakka and Lulu assuming sibling-like (perhaps even parent-like?) positions in Yuna's life. As such, they are naturally very protective of her.

Wakka and Lulu are constantly looking out for Yuna. They try to stop her from becoming a summoner when she first brings it up, but their efforts are fruitless. In spite of their opposition, the two of them become Yuna's guardians. Though they know that the ultimate end will be painful, they still want to go along with her. The topic is very sensitive and it is never brought up until the party nears the end of the journey.

An issue that cannot be avoided with Wakka is his prejudice against the Al Bhed. His blatant "racist" attitude towards them stems from his grief over Chappu's death - involving Yevon-forbidden machina - and so he has a bit of a shock when he learns that Yuna is half-Al Bhed. Even so, over the course of the pilgrimage, Wakka's distrust of the Al Bhed fades into respect, and he is able to come to terms with Yuna's identity.

Lulu is definitely more sensitive towards Yuna's feelings than Wakka. She really does act as a mother figure for Yuna, trying to steer her out of harm's way. Especially in the matter of Tidus - she doesn't want Yuna to develop feelings for him, just for those feelings to be crushed in the final battle with Sin. This is the reason for her initial apprehension towards Tidus, and even though she tries hard to protect the two of them, Yuna and Tidus end up falling in love anyways. When this happens, both Lulu and Wakka realize how important Tidus is to Yuna, and they let it go on, knowing that it is better than to separate them.

The two of them care deeply for Yuna. Everything they do is for her own good. Yuna knows this, and knows that she is causing them a lot of potentially unnecessary hurt by deciding to become a summoner. In the "post-Sin" sphere she made, she addresses them, saying that she really thought of them as her brother and sister. She also apologizes for becoming a summoner against their wishes. She owes them so much, and can only offer her words as consolation. In the end, when the party finds out about the requirements for the Final Summoning, Lulu is the first to volunteer to become the fayth. Wakka also does so moments later. Their devotion and loyalty to Yuna is unwavering - though everyone is appalled by the prospect of sacrificing a guardian to become a fayth, though it causes everyone pain, Wakka and Lulu are both willing to do it.

In FFX-2, Yuna tries to assuage Wakka's insecurities about being a father, and talks to Lulu about her concerns. This is, perhaps, paltry reward for what they did for her in FFX, but what Wakka and Lulu sacrificed for her sake is not something that is given up lightly. It is not something that Yuna can repay easily.