Sakuya is a form of Yuugi although they act nothing alike. Sakuya doesn’t know where she’s come from, she doesn’t know her family, and she doesn’t know her past.

At first, Sakuya hung around Tenchi because of her instructions imbedded into her mind so that even she doesn’t know that she’s receiving them. Yuugi wanted Sakuya become Tenchi’s girlfriend so that she could drive away the other six girls. Notice that when the six girls met Tenchi, they each received one of the crystals on Tenchi’s necklace. Those crystals helped defend earth. Yuugi couldn’t take over earth if the crystals were close together. The farther apart they were, the weaker. Unfortunately for Yuugi, Sakuya really did fall in love with Tenchi, and he with her. In the end, Yuugi took back Sakuya, and Tenchi has never seen her again.