Author's notes: This piece was originally posted on Archive of Our Own (AO3) on May 8, 2017. I intend to gradually shift my focus to that website.
Before the group ever left for the pilgrimage, Lulu knew one of them would not be coming back. While she wasn't a particularly devout follower of Yevon, she prayed just the same. Her prayers, though, were for drastically different things. Kimhari prayed for the safety of the summoner. Wakka prayed for blitzball victories. Yuna prayed for strength to complete the pilgrimage and defeat Sin to bring Calm. Tidus, well... he didn't pray, at least not seriously. He went through the motions to be respectful and avoid standing out, but he didn't actually pray.
Lulu's prayers were different. She prayed for wisdom to guide the young summoner, the way a good guardian was meant to do. She prayed for strength and courage in battle, not just for herself, but for all of them. She prayed for mental clarity. She even prayed for Wakka's blitzball victories, so that the party could have a bit of joy here and there. Most of all, Lulu of Besaid prayed for herself.
Sometimes, her prayers were answered.
Often, Lulu would dream. Sometimes it took a while to suss out meaning from her dreams, but she realized that she was being granted the wisdom and guidance she needed as a guardian. Occasionally, that widsom pertained more to her relationship with Yuna than it did to the pilgrimage itself.
The night of Tidus' arrival, Lulu had dreamed. Though she later could not recall the dream, she knew she simply awoke with a deep, unsettled feeling.
The only descriptor Lulu could attach to the feeling was "heartsick."
As the group sailed from Besaid to Kilika, Lulu watched the beginnings of her own undoing. Tidus would, in due time, win Yuna's heart away from the guardian. In the process, Tidus would himself surpass any of the others as a guardian himself. The dreams had granted Lulu that wisdom, but she simply couldn't keep herself from fighting back against it. After all, she stood to lose something more important to her, more cherished than her own life.
As the journey continued, Lulu's dreams intensified; the nights Yuna chose not to share her guardian's bed were the worst. The detail had not escaped Lulu, either.
Yuna's presence had always deeply affected the older woman. The journey itself fostered feelings of protectiveness bordering on possession. Those nights Yuna chose to sleep next to the mage sometimes brought forward the feelings of a jealous lover, sometimes they brought simple peace.
The reality of the situation began to settle on Lulu heavily. Tidus would win the girl's heart, and Lulu would let him. After all, she really had no claim to Yuna's heart, despite the younger woman's confession the night of her first summoning. A guardian's job was just that-to be a guardian. Lulu knew she was overstepping her bounds as she fell into the role of lover as well.
The words were never repeated until Yuna had taken them from the ever-watchful mage and given them to the boy from the sea. That night, Lulu concluded "heartsick" was the only appropriate descriptor for her feelings.
Gradually, Lulu realized what it truly meant, Yuna's gaining the ability to summon the Final Aeon. After awakening from the nightmare, her resolve set in.
Her sacrifice, to become the Final Aeon, was something she refused to let Tidus take away from her. In that way, she would always be Yuna's. Until her rebirth as Sin, she could belong to Yuna, share the summoning in a way no one else could. She could be the tool to give Yuna the Calm, the goal she'd sought for so long. The mere idea that she could lose that gift, that connection, that ability to be possessed instead of be the possessor left Lulu feeling heartsick.
Still, it came as a shock to hear, when Yunalesca told them the truth Lulu already knew. As she cast a sidelong glance at Yuna, Lulu knew she would support her summoner in whatever choice she made... Final Aeon be damned. With that, she darted ahead of her summoner into an insane situation.
Yuna's hope would never be crushed. Lulu wouldn't allow it. She wouldn't allow Yuna to become heartsick.