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".
There are several disputes about whether she's a monk or a nun. While in the official Game Profile and in the game she calls herself a monk, there are some who stick to the proper english term and call her a nun.
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. Namusan, or Namuamidabutsu(南無阿彌陀佛) is Buddhist counterpart of "Amen" in Japanese Buddhism, which can be found in most of prayers and rites.
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.
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.
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 is the the first last boss in the Windows era who is encountered not because she did something wrong. Like Remilia spread a scarlet mist blocking the sun, Eirin stole the moon, Utsuho attempted to destroy Gensokyo, etc. Byakuren was sealed away for trying to help humans and youkai and encountered the heroine not too long after being unsealed. Her alliance with youkai was dangerous and a threat to the heroines.
In the Chapter 12 of Oriental Sacred Place, Byakuren's hair is lighter on the top and gets darker towards the bottom.