The stage 6 boss, Byakuren has said that she was once a human and worked with her younger brother as a monk. When he died, she feared death, but she was able to maintain her youth with her power. However, she feared that she might lose her power, so she helped youkai in many ways. But she didn't hate humans either, because she wanted humans and youkai to co-exist. She was ultimately sealed away in Makai by humans. During the events of Undefined Fantastic Object, the youkai she has saved reappear to break her free from the seal. Her fate depends on which heroine is chosen by the player.
- Byakuren's name (聖 "Saint" or "Virtuous Monk" or "Itinerant Monk" + 白蓮 "White Lotus" or "Purity") can be read literally as "Saint of the White Lotus", "White Lotus Saint", drawing upon the cultural reading of the white lotus as a symbol of purity: "Pure and Saintly" or "Saint of Purity", or drawing upon the modern definition of 聖 (read as Hijiri, meaning a world-trekking Buddhist monk), "Roaming Monk of the White Lotus" or "The Pure and Itinerant Monk".
- Similar to how Yukari is called "Yukarin," it has become common to call her 「ひじりん」 or "Hijirin"
- Written in ZUN's hand on her final cut-in is 南無三！ (Namusan!), which is short for 南無三宝 - roughly, "Hail to the three treasures of Buddhism" (the Buddha, dharma, and the clergy). It's used to request salvation in a moment of danger.
- Myouren, Byakuren's younger brother, was a real Buddhist priest born in Shinano Province, which is ZUN's hometown, and trained at Chougosonshi Temple (朝護孫子寺) on Mount Shigi (信貴山). He appears in several stories, but the most significant one is Shigisan Engi, which is one of the most popular emakimono. In its third volume, there is an unnamed Buddhist priestess who wants to meet Myouren, who is her younger brother. She is the inspiration for Byakuren. The priestess is looking for Myouren because she is worried about him not coming back, so she stays at Toudaiji, where Myouren had made the vows for priesthood. Daibutsu tells her in a dream that there is a purple cloud over the side of the mountain southwest from where she is. She goes there the next morning, and finally she is able to meet and live together with him.
- Because of her and Minamitsu Murasa's relationship and character designs, some fans have described them as newer versions of Yumemi Okazaki and Chiyuri Kitashirakawa.
- Because she is a bit more mature-acting, and possibly because she is a Stage 6 boss like Eirin and Kanako (who are often portrayed as much older than the norm for the Touhou girls), some fan artists portray her as being an "old lady", or lumped into the same grouping as such. This is perhaps a bit ironic in Byakuren's case, considering how her profile states that she became a Magician to retain her youth.
- Curiously, at one point in her stage, the fairies move in a "Space Invaders" or "Galaga" pattern: shooting bullets, then slowly moving down.
- Some fans have suggested that Byakuren's clothes are similar to Rozen Maiden's Suigintou's.
- Byakuren's fourth Spell Card, "Great Magic: Devil's Recitation", looks like one of Shinki's attack patterns.
- She is considered something of a saint among some fans, especially when compared to the ruthless and self-centered nature of the heroines, who reject her ideals for peace. Other fans have argued that from the point of view of someone from a world where humans are oppressed, her appeals for human-youkai equality wouldn't make much sense. Others insist that Gensokyo is very close to if not exactly like her dream of a co-existence between humans and Youkai.
- There's the fact that things were just a misunderstanding, and that she ends up building a temple (perhaps with helps from the heroines) afterwards, which is sometimes said to be very popular with humans and Youkai alike.
- Some western Touhou fans compare her to Jesus Christ because she fought for youkai but got sealed away for their sins. Because of this, fans have affectionately dubbed her "Youkai Christ" or "Youkai Jesus".
- Byakuren appears on the cover of the UFO case.
- During her second-to-last (fourth) spell card on Easy, the stars under the health bar show she has two lives left. She does, but only on higher difficulties.
- Byakuren's actual hair color is somewhat up in the air. Most fans depict it as it appears (purple on the top, fading to brown), but other fans believe her hair is entirely brown, and it was the lighting of the stage or her scroll glowing that made it appear purple.
- Some fans did NOT take her usage of Shinki's attack pattern very well at all, most expecting Mima or Shinki to make an appearance in the Windows games after being practically forgotten about. The sight of Byakuren filling Shinki's attack stroked these fans the wrong way.
- Whether it was from the attack pattern or being in Makai, some fans speculate she has a relationship or acquaintance with Shinki and is shown in artwork, sometimes suggesting that Shinki taught Byakuren some of her attacks.