Name: Sakuya Izayoi
Abilities: Time manipulation, knife proficiency
Age: Estimated to be between 16 to 20 years old
Occupation: Maid, Manipulator of Time
Location: Scarlet Devil Mansion
(Touhou 9) Dark blue eyes, silver hair, has a long braid on each side of the face, carries many knives. Wears a pink and dark blue French maid's outfit with long sleeves, and a white bonnet on her head. The Roman numerals for 1 through 12 line the bottom of her apron.
(Touhou 9, alternative outfit) Same as above, but her outfit is mainly dark red instead of dark blue.
(Touhou 7.5, 8, 10.5) Same as Touhou 9 outfit, except her apron has no text and is wearing short sleeves.
(Touhou 7.5 and 10.5, alternative outfit) Same as above, but her outfit is mainly light blue with a white apron and her hair is light green.
(Touhou 7) Same as Touhou 9 outfit, except her apron has no text and is wearing blue colored long sleeves and a red scarf.
(Touhou 6) Same as Touhou 9 outfit, except she had bright red eyes, short sleeves, and the phrase "Red Magic" embroidered on her left sleeve.
Remilia Scarlet (Mistress)
Flandre Scarlet (Mistress's younger sister)
Patchouli Knowledge (Mistress's friend)
Hong Meirin (Scarlet Devil Mansion's gatekeeper, occasional punching bag)
Eirin Yagokoro (Unknown)
Embodiment of Scarlet Devil (Stage 5 Midboss, Stage 5 Boss, Stage 6 Midboss)
Perfect Cherry Blossom (Playable Character)
Immaterial and Missing Power (Playable Character, Possible Opponent)
Imperishable Night (Playable Character)
Phantasmagoria of Flower View (Playable Character, Possible Opponent)
Shoot the Bullet (Stage 7-1, 7-3, 7-5, 7-7 Boss)
Scarlet Weather Rhapsody (Playable Character, Possible Opponent)
Easily one of the most enigmatic characters, despite appearing in so many games, Sakuya is the Chief Maid at the Scarlet Devil Mansion. She works for her mistress, Remilia Scarlet, and is apparently the only human working at or living within the mansion. She has the power to stop time. She is known to then place knives in midair and resume time to allow these knives to fly towards her targets. Stopping time is also a handy way of doing large amounts of maid work in a short time. Because nearly everyone living or working at the mansion are maids, being the chief of them all means there are few people there with more authority within the mansion than Sakuya.
During Embodiment of Scarlet Devil Sakuya attempts to prevent the heroine from reaching her mistress to whom she is very loyal, but fails. Later, during Perfect Cherry Blossom, Sakuya is able to show more of her true character, even if her main reason for trying to solve the problem is that the delayed Spring will affect her too.
The characters for Izayoi literally mean "Sixteenth night" (the night just after that of the full moon), and Sakuya "Flowering night."
Sakuya Izayoi is apparently not her real name, according to Perfect Memento, but is only a name given to her by Remilia. Her real name is unknown.
Since Sakuya has tremendous skill with handling knives, she is extremely good at cooking.
According to Sakuya, if she happens to run out of knives, she can freeze time and pick up the ones she threw previously.
According to ZUN, "Manipulation of Time" is synonymous to "Manipulation of Space." She takes advantage of this fact in several ways, from enlarging the space inside Scarlet Devil Mansion, to probably storing an immense amount of knives around. Maybe it's general relativity?
Sakuya can also use her powers to accelerate time, such as making bamboo flowers bloom instantly, even though this would normally take sixty years.
Sakuya may be an homage to Dio Brando, the main villain of the manga series JoJo's Bizarre Adventure, a vampire who is known for stopping time and being skilled at throwing knives. (ZUN has also referenced JoJo's Bizarre Adventure in Remilia's dialogue and Shoot the Bullet Scene 65. Sakuya also takes the same pose as Dio with one of her moves in Scarlet Weather Rhapsody, and has a Spell Card in EoSD named "The World," which is also the name of Dio's stand).
Sakuya "prepares" food for Remilia and Flandre Scarlet. It's a mystery how this is done exactly, although she mentions in Phantasmagoria of Flower View that with so many flowers around, she can make as much tea and as many pastries as she wants. (Flowers have often been used to provide flavoring for tea, especially in the past, and are still the basis of jasmine tea.)
In some fan-produced works, Sakuya is depicted with dog ears and a tail, probably a reflection of various characters referring to her as Remilia's dog. For example, in Sakuya's scenario of Perfect Cherry Blossom the three Prismriver Sisters offer to make her a part of the banquet by eating her. Lyrica starts singing "dog meat, dog meat", implying that Sakuya is a dog. Sakuya is the only one of the three heroines available that the Prismrivers threaten to eat. In that game, Yuyuko names Sakuya "dog of the devil".
Another recurring joke with fans is the idea that Sakuya pads her chest to make it seem bigger than it is and goes to great lengths to hide this secret, even from Remilia herself. The origin of this joke was due Sakuya's portraits in Immaterial and Missing Power, which for some reason showed her with larger breasts than were seen in all of her other ZUN-made portraits (with the possible exception of Embodiment of Scarlet Devil).
There have been several clues spread across the Touhou series that suggest that Sakuya may not actually be human. Most of these occur in Imperishable Night, where Eirin Yagokoro is surprised to see her (according to Eirin's profile). In another scene, she survives staring at the full moon (which should drive humans insane, even though Marisa, Youmu and Reimu survive staring at it as well...). She has silver hair just like Eirin and uses silver knives, both the color and metal silver representing the Moon in many contexts. In Perfect Memento, Hieda no Akyu agrees that Sakuya probably does not come from Gensokyo, and the description of Kaguya Houraisan's powers are quite similar to Sakuya's time manipulation. These all seem to point to the possibility that Sakuya may in fact be Lunarian. (Some doujin artists have attempted to explain the relationship between Eirin and Sakuya in their stories. These range from the ideas that Eirin created Sakuya's Lunar Dial, but prolonged usage erased Sakuya's memory, to the two of them even being sisters.)
Meiling and Sakuya are the only characters in EoSD to have their long sideburns in braids.
Her alternate outfit in Immaterial and Missing Power and Scarlet Weather Rhapsody is an homage to Ruukoto, the series' first maid. In Touhou Hisoutensoku more alternate outfits were added, including a Shinku palette and a Dio Brando palette.
Since the announcement of Undefined Fantastic Object and of Sanae Kotiya as the only new playable character (along with Reimu and Marisa), parallels were immediately drawn with Sakuya, the first playable third character of the Windows games. Sakuya or sometimes Youmu was the titular reoccurring side-protagonist until later in the series (Mountain of Faith, Subterranean Animism), when she was completely omitted and unmentioned. Jokes and fan art of Sakuya being venomously jealous of Sanae's newfound popularity and prominence commenced