This is completely a fan's interpretation, and shouldn't be counted as to Touhou canon.
Patchouli Knowledge (Pronounced "No-ledge") is one of the three founders of The Organization, although she isn't so much of an active member of the Council to this date. She currently resides within the Scarlet Devil Estate, finding books as a means of comfort and passtime, and it's due to the fact that she spends so much time, that she's called "The Great, Unmoving Library"
|Chronological and Physical Info||
There are tales of a young girl, the young girl had herself locked inside of her room, whatever books she had read had substituted for school and saved her parents money due to the case of an eidetic memory. Patchouli was born before the time of the first World War on Earth, specifically in London. Compared to her family, she was often captivated by books she'd read in her room compared to playing outside. Ultimately, she had self-educated as she furthered her reading, becoming college level before being a young adult. Later on, this led to an obsession of gathering books to amass a library, something she always wanted to start locally in London. Because of the lack of a substantial outcome, however, Patchouli had quickly given up on the dream, as spending her time inside has made her out of shape and thus, unable to perform physical tasks.
The means for income would come to light, however - decades after: as she had a chance encounter with Snipes, a master thief and amateur alchemist at the time. They had later on formed a partnership, however, Snipes in turn, had done most of the work, while Patchouli read up on less-favorable devices. Ultimately, she had been in control of the money, although figured that she couldn't start the idea of a library because it's stolen money. Instead, she let him lead the money decisions after, which he chose to help the impoverished people, but never during the events of a recession, as that would make him not only a target, but people ultimately suspicious of him. Legends of a golden comedy mask wearing man had became synonymous with a phantom thief with his eerie grin.
In turn, to help cover up her partner's actions of playing Robin Hood half the time, Patchouli had used her mass of deductive logic to work as a detective for hire, and eventually the constable force, only to have to exercise to improve her physical being and health (she described it as something akin to being put through Hell). Patchouli had turned up with "Blank" searches, her often stoic face being difficult for telling if she had truly lied or even told the truth. Although with many successful cases ramping up, people merely bought it that even the thief could stump their top detective. Aside to reading into the occult books, one of which was stolen by Snipes, Patchouli had taken an interest into looking towards macabre horrors which were homicide cases, eventually, handling the case for Jack the Ripper.
During this time, she still forwent any sort of firearms, in use for combat. Instead, she had turned to the use of occult magic. She's already bound a (lesser?) demon to her will, at the guidance of a teacher that had taught her the wealth of magic. After her teachings, she (Patchouli) had accidentally in turn, summoned two more supernatural beings. This time being a pair of sisters from Romania. Patchouli's stoic behavior prevented any sort of claim the older had given her. Despite the older claiming to manipulate fate, Patchouli wasn't so much as intimidated by the case, and had rebutted it with strong cases of wit. Patchouli had then amassed a team of four, ultimately with their help, she got to the bottom of the case of Jack the Ripper, although not without the older sister's help. Jack the Ripper wasn't a woman, nor a man, but a small child with the ability to wield knives with definite precision. The fight was near it's end, where Patchouli could've had the situation costing her life, only to've been saved by the older of the two Romanian sisters.
During this intermission, Patchouli and Snipes had went dark after the case, having disappeared off the face of the earth, thought to've retired. The two had actually decided to go into dimensional travel with a third associate. The three had through their connections, eventually formed the Trinity Organization, a group where demons, youkai, and humans (represented by Kass, Patchouli, and Snipes in respective) all alike can work towards common goals, in hopes of furthering the diplomacy between all groups. While the event was widely unaccepted and unsuccessful, Trinity was joined by many sympathizers to the case, and eventually grew in what most would've considered a large cult following. In the result, of course, it had grown much bigger than anyone had thought.
In actuality, where she could stay during this dimensional travel? Patchouli had attended to a Romanian estate from the two sisters, and ultimately made it a place to settle down. She had finally used her funds to buy books from all over the world, having made a library out of what was the finished basement. It's said that Voile was massive enough that one could compare it to the size of a cathedral. When she had ultimately scratched her dream, she wondered. What if such a case came to where she couldn't be the one to take care of the library? She couldn't just leave it to Koakuma, her first servant. And leaving it in the hands of the Romanian sisters, otherwise more or less known as the Scarlet sisters now, would just lead it to disrepair due to the various maids doing everything for them.
This meant that she ultimately had to raise a family. The thought didn't appeal to her that much then, she was a little young, but for now? It seemed like yet another goal. Snipes was the only man she considered a "partner", and so due to the fact that going out in the open would shock the region, she conceived five children in all, and kept it a secret, even from the Scarlet sisters. It was a well-kept secret for the most part, until after eleven years of raising them all, Snipes had eventually tired out of not only being cooped up in an estate, but now how uneventful and not exciting his current life was. He had eventually resulted to leaving the family that he had known for so long, going off on a grand part of an adventure in a quest to search for immortality.
Patchouli was devastated. The first friend she had ever made, the man that she had chosen to love and raise a family with, had left on a selfish desire to prolong his own life and enjoy himself. How could someone she knew turn out to be so hedonistic? The thoughts had tore at her mind, and eventually, she turned to the only true thing she found that was there for her all her life. Books. She continued to read, and read, neglecting her children to the point where Koakuma couldn't even continue to watch anymore. Unsatisfied with the end result, Koakuma had taken the children and had abandoned them (the younger two) or gave them to family friends (the middle offspring and the only son) to raise as part of the family, left with clues to their actual being.
Patchouli had resigned to this choice and had never really put anything onwards the idea, instead, she had continued to read her books. Her health had ultimately deteriorated, catching the full brunt of unattended to asthma, which affected her more because her lungs declined in health, as well as contracting anemia. To this date, she stays in her library, reading a book to mask the pain, and eventually forget. Eventually, however, her son had turned up at the estate to find her. The only proof he had was a copy of the grimoire that she had made during her stay in Trinity, having initially hoped to teach her children to leave, so they could learn to love books as she had.
She felt something break, let alone heard it. It was like glass, but she looked around to find that nothing had broke. What had truly broke was the mirrors inside her mind going on about the broken dream. Her son, through deductive logic and information given, like a detective at that, had ultimately followed in her footsteps, (figuratively and literally) to find her. While not the most ideal successor, as she saw her ex-partner's face in her son's own, (sans eyes), that aside to her son's wanton violent behavior. Despite this, he's seemingly taken the most to her, aside to the two younger twins, which he had found along the way and saved from poverty.
There are tales of a young girl, the young girl had herself locked inside of her room, who could never have imagined herself in this sort of life. And now the girl is a wizened woman, content, and ultimately satisfied with the outcome. She had returned to her rampant pursuit of knowledge and book reading without a somber aftertone, and on occasion, showing glints of emotion to show that she wasn't as lost after all.
She is known to be a very intelligent and clever being, although often stoic. As her last name states she has much more information then most who interrupt her reading. She however is a non-moving fortress of "Knowledge" due to her views on how her vast Library is, and how little interest she finds out in the real world. Yet, she only finds out what is going on outside her Library is if someone brings it to her, or she pummels an intruder out of what she needs to know. It is known that she will do anything to get the information she needs to further her own understanding of something, as such, she is definitely obsessed with the obtainment of knowledge, if it's outside her bounds. She once stated that "I'll simply understand everything there is." if she can't figure out the most important answers.
She is also a very dark person. Not as in evil, just rather reserved. Her Library is placed under the Scarlet Devil Mansion. Yet even after making such a trip underground, one has to choose between several fake entrances to get there. She has been noted to have left her Library only twice since her arrival in the Scarlet Manor. Once during a Summer where the well known Reimu Hakurei held an event for all residents, and during a time with an Immaterial Missing Power flowed through her library. She has also been deemed as expressionless. She isn't, yet she doesn't find a great deal of happiness as she reads, nor with intrusions, her past, or those who borrow or steal books not to return them.
Her non-plussed face only ever seems to change with her family, and or assistant helping her. Koakuma or "Koa" for short aids her in cleaning, organizing and alerting her "mistress" as she calls her of a situation. Patchouli being the name of a flower, has the mouth of a thorn. She doesn't swear, yet her comments and come backs are highly insulting, and very witty. They usually leave for a long pause after such a well made remark, or the feeling of confusion if the statement wasn't caught the right way or at all. It's said that back then, she showed more emotion than her stoic face, and when met up with her offspring, she sheds the cold exterior, as much as she'd try to keep in. It is only rarely that she maintains the emotionless charade that she puts up, having a bit of acting to her everyday side.
Her biggest peeves is not knowing something that was rather easy to have gotten which is a rare occurrence for her and leaves her with more questions as to why she didn't grasp such a topic, and rats. She has been known to call those who snoop or sneak around her such. Another witch known to do so named Marisa Kirisame an inspiring magician willing to learn magic and borrow all the tools needed to do so is no stranger to such a name. Also, none quite know how many books she has, or how long it took her to gather them all, or how such a acre long place can be inside a mansion.
Her magic is quite strong against all who face her. The type of magic she uses corresponds with what day it currently is. For example: On Sunday would be the day of Sun, as she uses fire type magic specifically on that day. She states "Now you will see my best magic". She is also able to use a light sword made of many sharp light wise ends, crystals for healing, and boosting her own strength. She can use her small black or brown colored spell book as a weapon as well. It isn't known how many spells she knows, but the one she is well known for is "Royal Sun Solar Flare". She uses spell cards to bring out her magic unlike other witches who use a wand, as this attack severely burns her foe, mimicking the heat of a sun. However with any fire attack she uses, it causes her asthma to arise as she may cough for some time before regaining her composure. It may be due to all the dust that lingers in her Library, or from birth.
Patchouli's mind is also an ample weapon, being a natural with deductive logic, and allowing her to accurately predict when her opponent's up to. She always uses this logic to plan out her next move, only coming to a huge flaw if her asthma attacks straight at that moment. While not being in the best state of health, she is able to dodge back and forth in rapid succession, even to the extent of using magic to afterimage, while holding the resplendent grace in form. This grace also extends to how she casts her spells, even spinning and twirling to pull it off. This shows that she hasn't lost such a big amount of the fitness she had previously held from detective and police PT during the time than what was previously thought.