The Spread Shot of Sakuya Izayoi and her buddy, Yukkuri Sakuya, from the world of Yukkuri Bullet Battles (a Touhou LW original). She unleashes a yukkuri attack. Scarlet Devil Mansion Town is a famous location where Buddy Battlers gather for Yukkuri Buddy Battle tournaments. Sakuya acts as the town's de facto sub-leader. Yukkuri Buddy Battles (YBBs) are an offshoot of this world's Spell Card Rules. The girls who participate in YBBs are called Buddy Battlers (BBers), and the stronger her bond with her yukkuri, the more points she scores for beauty. Though the term BBer is gender neutral, only girls are known to be BBers.

The Focus Shot of Sakuya Izayoi and her buddy, Yukkuri Sakuya, from the world of Yukkuri Bullet Battles (a Touhou LW original). She unleashes a yukkuri attack. Sakuya is a tough BBer who fights using her time-manipulating yukkuri buddy, Yukkuri Sakuya. She may be a yukkuri, but Yukkuri Sakuya is no joke. Together, she and Sakuya have complete control over time and space, and are often seen toying with their opponents. The way they fight in perfect sync has garnered them the nickname "The Perfect and Elegant Buddies."

A Spell Card of Sakuya Izayoi and her buddy, Yukkuri Sakuya, from the world of Yukkuri Bullet Battles (a Touhou LW original). She unleashes a special yukkuri attack. A BBer and her yukkuri buddy are always together. When Sakuya is busy with her maid duties, Yu-Sakuya is there to help. She goes beyond imitation, copying Sakuya's workstyle flawlessly. Even without hands or feet, there's almost nothing a yukkuri can't do. And because BBers and their yukkuri buddies spend so much time together, they're extremely close. They eat, sleep, and even bathe together.

A Spell Card of Sakuya Izayoi and her buddy, Yukkuri Sakuya, from the world of Yukkuri Bullet Battles (a Touhou LW original). She unleashes a special yukkuri attack. Many mysteries still remain around the strange abilities yukkuris use. BBers like Sakuya can fire bullets themselves, but in YBBs, that's strictly forbidden. Aesthetics play a huge role, and it's considered far more beautiful for the yukkuris to fire the bullets instead. That's right―yukkuris can fire bullets too. They even possess their own unique abilities. In Yu-Sakuya's case, her bullets closely resemble Sakuya's. There are countless similarities between BBers and their yukkuri buddies. The question is why.

The Last Word of Sakuya Izayoi and her buddy, Yukkuri Sakuya, from the world of Yukkuri Bullet Battles (a Touhou LW original). Her yukkuri buddy transforms into their Lunatic Buddy form. There are still so many mysteries about BBers and their yukkuri buddies. Even in a world where yukkuri studies have advanced so far, there's still plenty no one can explain. Naturally, that applies to Sakuya and Yu-Sakuya. Sakuya is a dedicated, no-nonsense maid. But every now and then, she'll say something completely out of left field or pull off some outrageous stunt. You'd think Yu-Sakuya would just be a less intense version of her, but she can be even bolder than Sakuya. When they're off duty, the two of them occasionally head into the city. They call it their "maids' me-time," but it's just an excuse to enjoy some casual Yukkuri Buddy Battles. After all, if people realized they were from the Scarlet Devil Mansion, they wouldn't dare to challenge them. "I remember one time, during the Scarlet Mist Incident, Reimu, Yu-Reimu, Marisa, and Yu-Marisa stormed into SDM town. Me and Yu-Sakuya drove them off, though. Oh, and there were those other times, when we took on Yu-Yuyuko and Yu-Kaguya..." As Sakuya reminisced to herself, her Yu-Cube began to glow with an eerie, lunatic light. ...Wait, what happens when it glows again?