Sakuya is Eureka's predecessor, a girl with lavender hair and mysterious powers that made the religious order of Vodarac believe she was some kind of messiah. They confined her to the temple's central chamber and basically isolated her completely—no disciples were allowed to talk to her, and only a select few could tend to her needs in an austere, reverent way. For forty years, she had almost no human contact at all.
That changed when Norb was assigned to care for her. The two fell in love, and despite trying to keep it quiet, a priest caught them embracing. The priest took this as a sign that Sakuya had chosen someone to travel with into the Scub Coral, so they were rushed into the zone before either of them was ready. The crossing went badly. Both of them were physically warped by the experience, though Sakuya got it worst—she was transformed into a giant lotus flower.
After her transformation, Sakuya created a barrier around the temple city that sealed everything off, including trapar, which had become toxic to her. Eventually, Norb brought the Gekkostate to meet her because they needed her help getting Renton and Eureka through the Great Wall. Eureka encountered Sakuya in some kind of other reality—a library space where they discussed their pasts and how Sakuya and Norb had first found each other. Once Eureka headed back, Sakuya and Norb dismantled the barrier and channeled its energy to help Renton and Eureka cross through. In the end, Sakuya and Norb were taken into the Zone to be together, while Renton and Eureka made it to Earth.
Content compiled by AnimeList.moe from publicly available sources.
