Aoko and Touko's grandfather, the third generation head, raised Touko in the way of the magus in his Workshop on the mountains, while Aoko and her parents lived separately. When Eiri Fumizuka apprenticed under Aozaki clan, he was in a relationship with Touko. She was a student at the Reien Girl's Academy, where she became an acquaintance of Mother Riesbyfe.
However, when the two girls were 18 and 16 respectively, he suddenly changed the position of successor to Aoko, despite Aoko being a formally inferior magus (not counting her ability to "blow things up"). Shocked, Touko killed him right after he passed down the family heritage to her sister. Because of this Touko does not share a particularly good relationship with her sister.
Entering the Mage's Association
When Touko was a teenager, she entered the Clock Tower academy to get her revenge on her sister who stole the rights of the Family Head of Aozaki Clan. She was a student along with Souren Araya and Cornelius Alba, they were a part of the Department of Universal Research. Touko rose to the rank of Master when she was 20 years old.
In her graduation, Touko wanted to earn the title "Blue" but instead she was given title "Red", this caused Cornelius envy and hatred as he wanted the title "Red".
All three were in good terms until they left for their own research. She studied the human body while aiming to recreate the original human body, She stated in Paradox Spiral that she left the research under the belief that modern humans could no longer reach Akasha after becoming too diversified genetically.
Leaving the Mage's Association
Apparently, Touko is getting money from Mage's Association using her sister's name.
She bought Lugh Beowulf and gave him the name "Beowulf." They went on a number of exploits across Europe, and he remained undefeated throughout them. Some involved a train that collects mystic eyes, an ancient giant octopus living in the North Sea, the Bermuda triangle, which leads to another world, and an Elder Title Dead Apostle Ancestor.
Hall of Monastery
In the 90's, she runs a kind of detective agency Garan no Dou (Hall of Monastery) that only engages in cases with supernatural or abnormal elements. She placed a bounded field around the building that houses Garan no Dou that was supposed to make it undetectable via hypnotic suggestions, and made it into her workshop.
It is unknown how she met Azaka Kokutou but Nasu hinted that Tobimaru Tsukiji might be involve in how they met. She later took Azaka as her apprentice and developed the salamander glove to strengthen and better control her ability.
She is shown as a artistic puppet maker and as an occasional designer of buildings, she designed the Ogawa apartment spiral complex.
In her original design, she had short blue hair. But her character design changed when Kara no Kyoukai film released.
In the Character Material, her appearance is a school girl with long black hair.
A heavy smoker, she is stated to always have a cigarette between her lips. According to her younger sister Aoko, Touko "looks like an educated mom with spectacles and a cigarette".
In Kara no Kyoukai, she wears a long brown trench coat.
Touko was originally obsessed with reaching the Akasha which led her to hate her sister. She was also very competitive with Araya, as both were trying to reach the Akasha, but eventually she gave up on it. While giving up on it, she enjoys her daily life with people she cares about. She usually cut ties with people and she realised that she stayed too long with Mikiya, Shiki and Azaka.
Touko can easily change her personality depending on the situation how she views, for example when she first spoke to Mikiya on the phone she had a serious tone to appear important, whereas when she meets Mikiya in person, she seemed nice and friendly.
She is also very loose with money, she buys items with magic properties on impulse which leads her to being broke months at a time.
She is easily roused and lacks patience. For example she hates being called "Dirty Red" and she broke her own rule of constructing a new puppet and went directly to Alba for revenge.
Mahou Tsukai no Yoru
Touko is an antagonist appearing before Aoko, Alice and Soujuurou Shizuki, she bring Lugh with her to fight against them.
After Soujuurou defeated Lugh, Touko killed Soujuurou in front of Aoko by ripping him apart.
Touko was eventually defeated by Aoko and her 5th Magic.
Kara no Kyoukai
In Kara no Kyoukai, she plays as the knowledgeable magus giving insight to the abnormalities situations.
Chapter 4: The Hollow Shrine
In May 1998, Mikiya Kokutou saw her puppets in the museum and was drawn to them; he sought Touko's workshop and was able to find it, regardless of the bounded field. Because of that, she acknowledged his talent for "finding things" and became his employer.
In June 1998, Shiki Ryougi awakens from her coma, and Touko replaces Araya as the new counselor and introduces herself to Shiki as her speech therapist. Touko explains to Shiki that she is confused and frightened due to losing her other personality. She visits Shiki everyday which Shiki realizes she is dependent on their conversation. Before leaving she placed a rune Bounded Field to protect Shiki from spirits.
When Shiki tried to destroy her own eyes during in the night, Touko stops her claiming it is a waste and explains her new abilities.
When a Wraith possess a dead corpse and entered Shiki's room to claim her body. Touko tried using her rune spell to burn the dead corpse but it was ineffective. Touko suggested to retreat but Shiki refused and successfully killed the Wraith.
Touko then offered to teach Shiki how to use her abilities in return for her services as she lost her familiar, to which Shiki agrees.
Chapter 1: Overlooking the Scenery
In September 1998, she and Mikiya were investigating the recent suicide at the Fujou apartment. She warns Mikiya not to go near the building but Mikiya didn't listen to her and was caught in a unconscious state by Kirie Fujou.
She explains to Shiki about the suicide cases and the abnormalities that led Mikiya's unconscious state.
After Shiki loses her artificial arm, Touko repaired and upgraded her Magical Prosthetic.
After Shiki defeats Kirie's spiritual body, Touko visits Kirie's physical body in the hospital. She asked a few questions on her incurable condition and the reason why she killed the other girls. Touko leaves the hospital after questioning her.
In the Epilogue, Touko is walking near the Fujou building with Azaka, where Fujou's corpse has been found. Azaka couldn't understand why she committed suicide and Touko comments that she just probably could not fly today.
Chapter 5: Paradox Spiral
In November 1998, Touko was contacted by a police friend about a strange case involving with the Ogawa apartment complex. She knew something was odd as she was the original designer so she asked Mikiya to accompany her to the apartment. They found many abnormalities and Touko notice Alba spying on them.
She meets Alba in her exhibition. Alba revealed about the apartment plans and the kidnapping of Shiki. Touko took this as an offense towards her. Touko realized even she was involved in this, she wanted to solve this alone to save Shiki and protect her current lifestyle.
She went alone to the Ogawa apartment bringing along with her Projection machine. She meets Alba who challenges her. Touko suggested to bring out Araya as Alba wasn't capable of facing her. In the original novel she redirects Alba's thousand degree sea-of-flames spell, and nonchalantly uses it to light her cigarette. Alba was swallowed by the cat familiar and knocked out but Araya saved him. She faced and seemingly defeated Araya with her Projection Machine but Touko soon realized the Araya she defeated was a puppet. She was later incapacitated by the real Araya when he pulled out her heart from behind. However she did not die as Araya kept her in a frozen state, he decapitated her head by ripping her head from her body and stored it in a jar.
Araya handed the head to Alba. As Alba was about to leave, he saw Mikiya and, believing him to be her apprentice, attempted to torture him and cursed Touko's head.
The puppet who awakened after Cornelius killed Touko disobeyed her own rule of "begin activity after constructing a puppet" and went straight for Alba bringing along her familiar 'Sealed Box'. Cornelius was devoured by Touko's 'sealed box' after calling her by her nickname, "Dirty Red".
After Alba death, Touko provided first aid for Mikaya. Araya was peeking at Touko, asking if she wants to resume the fight but Touko claims its foolish to fight him again inside the building even if she has chance of winning with her Sealed Box. Touko laughs at Araya, for his mistake to imprison Shiki within a barrier isolated from space rather than locking her physically. She revealed to Araya that Shiki can cut down his barrier to escape which caused him to suffer pain from inside as the Ogawa Apartment is linked to his body.
As the Apartment crumbling down, Touko grabbed Mikiya and evacuated straight away. After Araya's defeat by the hands of Shiki, Touko and Araya had their last conversion together. Touko expresses that his downfall was caused by Enjou Tomoe's love for his family as well as his breaking out of the cycle created by Araya. Touko revealed that his name is the same thing he detest before he died.
In the epilogue, Mikiya revealed that Touko dispose of the corpsed found in the ruins in the Ogawa Apartment.
Chapter 6: Oblivion Recorder
In Januray 1999, Touko asked Azaka and Shiki to investigate the case involving with a magus controlling Fairies in the Reien Girl's Academy.
Shiki and Azaka found an old photo of her when she was a student and a brief moment brought the two laughing together.
Chapter 7: Murder Speculation Part 2
In February 1999, Touko talks to Mikiya about the recent murders connecting with Shiki. She allowed Mikiya to take some time off from work to learn the truth.
She called Daisuke Akimi about the recent homicide case; Touko went to investigate the crime scene and agrees with Daisuke that the recent murder and the case 4 years ago are related.
After Lio Shirazumi leaves Mikiya and warns him not to approach him again. Mikiya asked Touko if she'll be able to help Lio. She reveal details about origin and that it is impossible to help Lio in his current state. As Mikuya went to search for Shiki, Touko wish him well and hopes fate allows them to meet again. Azaka barges in complaining about Mikiya relationship with Shiki and wishes him to cut his ties with her. Touko realized that she stayed too long and she's planning to leaving.
Touko is referenced in the epilogue of the Heaven's Feel route of Fate/stay night, but she goes unnamed. After Shirou Emiya's body was destroyed, they required a puppet body for him after he was partially restored by the Third Magic. They sold the books at the Matou house to obtain a body left by a famous puppet maker, but it has some problems because it was obtained used. It is still the best one out of all those they tried, so they wish to look for her to obtain one that matches him. They note that it will be hard to find the creator because she is marked with a Sealing Designation and on the run from the Mage's Association.
Touko has an alternate counterpart in Fate/Extra who appears with an alternate version of Aoko in the Moon Cell. She has brief cameos in Carnival Phantasm.
She's a powerful magus and Touko has 20 Magic Circuits, which was a surprise to the Aozaki clan as the number of Magic Circuits in their line had been dwindling. Due to her formidable power, Mage's Association dubbed her with the color Red, which is close to the three primary colors. She wished to get the color Blue, but that title was taken by her sister Aoko. Although powerful in modern standards but she is still incapable of facing a serious Caster.
She is able to create a Bounded Field around Shiki's hospital room with the help of a rune stone, which prevents the entry of spirits. One Wraith manages to find his way inside of it by possessing a dead corpse. She is also proficient in using rune-based thaumaturgy. One of her rune spells, Ansuz can kill a human easily by burning the heart but it's ineffective against dead people.
While she jokes half-seriously about only being able to fly with a broom, she actually patented a new type of flight most commonly called "Touko Travel."
Touko smokes Dragon Smoke cigarettes very frequently. They were made in Taiwan, and they are of poor quality. The maker has since disappeared , and only one cardbox-full was ever made by a curious craftsman. They are the second most valuable item in Garan no Dou. She often uses them to write her runes in the air.
She is an expert on Mystic Eyes and she created glasses that can hold back property of the ability. The glasses Shiki Tohno wears were originally made by Touko. Her sister Aoko stole them from Touko and made them indestructible.
As a doll-maker, she received a Sealing Designation for creating a doll (body) that was an exact replica of her own body. She's able to reproduce parts of a body that can be used instead of the lost part. While this would be nothing special, she can reproduce the part in such a perfect way that it comes close to the real one.
Touko's puppets are stored all over the world. After one dies, the active, next-in-line Touko (puppet) will awaken. Touko (puppet) will first construct a puppet of herself, and then go outside to start her hunt for pretty girls. However, whether she inherits the will and goals of the original will depend on her location. The closer the puppet is to the original, the more likely she will inherit the original's will. If the puppet is activated from a site that is too distant, a blank in her memory proportional to the distance will form.
She crafted Ryougi Shiki's arm and Shirou Emiya's body in Heaven's Feel.
This puppet appeared in Mahou Tsukai no Yoru. Touko crafted it to resemble her little sister, it has 4 arms with a crow mode and a spider mode. It can self-destruct.
Created by Touko Aozaki to replace the familiar that was destroyed by her sister.
It appeared in Kara no Kyoukai: Paradox Spiral. A suitcase with a projector installed inside. It shapes Ether Clump in the form of a monstrous cat that cannot be destroyed unless the suitcase is destroyed. It also has the ability to heal Touko by enveloping her.
Another of Touko Aozaki familiars, a black monster with a thousand mouths and thorn-like tentacles stuck inside a box. It drags its victims to inside the box so it can eat them.