- Reimu seems to be scared before and after the boss battle with the Five Magic Stones, thus making this the only ever time that Reimu was scared and/or afraid of a boss before and after the battle.
- Most of her theme from Lotus Land Story sounds similar to Elis and Kikuri's theme from Highly Responsive to Prayers, "Magic Mirror".
- It is originally stated that she lives alone at the shrine, but other rarely seen characters (Mima and SinGyoku) are known to stay there or near there as well.
- In Imperishable Night, Reimu is the only one whose partner doesn't mention the danger of the full moon.
- In Touhou Hisoutensoku, if you activate Fantasy Temperament successfully in a 3rd round, a remix of "Eastern Mystical Love Consultation" will play with the sounds of the Fatal KO theme from the Hokuto no Ken fighting game, fitting because activation of the said Spell Card means the opponent is certainly already dead! Because of this, it is now known as the Hakurei Hyakuretsu Ken to some extent to the fanbase.
- In Touhou Hisoutensoku, one of her alternative palettes looks similar to VIVIT, the heroine of the Seihou Project. Also, one of her palettes seems to be another maid homage, Ruukoto, or possibly Sanae Kochiya's colours. The palette also seems to resemble Mima from Highly Responsive to Prayers. Her white/light gray palette seems to resemble Toki from Hokuto no Ken.
- When playing Yukari's story mode in Scarlet Weather Rhapsody, Reimu breaks down in tears in the ending after Yukari defeats Tenshi and reduces the Hakurei Shrine to rubble for the second time, with Sakuya and Youmu looking on helplessly (although Suika offers to help rebuild it). This marks the first and only time where she is seen crying in a storyline scenario.
- The shrine maiden at the end of Dolls in Pseudo Paradise is probably Reimu. She has Reimu's title, "Shrine Maiden of Paradise" (and her personality), and according to Bohemian Archive in Japanese Red's Music Column, the shrine maiden in the song that accompanies the ending section is Reimu (so basically, this shrine maiden has Reimu's song and title). However, only the shrine maiden at the end is referred to as the shrine maiden of paradise. Thus it is possible that the shrine maiden seen in the first half of the story is a different person altogether.
- A "13th Shrine Maiden" signs off the Gensokyo Record in Perfect Cherry Blossom's prologue. ZUN has stated in an e-mail that the Gensokyo Record is unreliable (for one thing, the writing style of each section shows it was written by a different person each time), thus "there is a high possibility that Reimu is not the 13th Hakurei shrine maiden." (technically, this also means there is no proof that the person who wrote that section of the record is a shrine maiden at all).
- It is shown in Oriental Sacred Place that the shrine sometimes gets various donations (including wine) from unknown sources (implied to be from the outside world, as the Hakurei Shrine lies on the border) and Yukari is shown in Oriental Sacred Place to sneak yen donations into the offering box when Reimu isn't looking.
- Although Reimu has successfully resolved the incidents in each major Touhou game, it's possible that her win rate throughout the actual events of the games was not 100%. Perfect Memento in Strict Sense states that Reimu likes to request rematches until she finally wins (something which is allowed under the spell card rules). In essence, Reimu apparently has had to use a few continues every once in a while, but she still manages to get a good ending.
- Marisa is one of the most frequent characters to appear in the Touhou Project series, only second to Reimu after the release of Fairy Wars.
- Marisa has six theme songs (excluding remixes), making her the character with the most theme songs.
- Including spin-off games and Shuusou Gyoku, Marisa has appeared as an EX boss two times more than any other EX boss.
- Marisa has appeared on the covers of Story of Eastern Wonderland, Phantasmagoria of Dim.Dream, and Lotus Land Story.
- According to Rinnosuke, Marisa was inspired to use star-themed magic after a meteor shower viewing party around 2001 to 2002. Marisa's strategy guide in Story of Eastern Wonderland's omake says her third attack uses star magic, although that is just one attack. However, by the time Phantasmagoria of Dim.Dream takes place, many of her attacks use stars. Her apparent mentor Mima also had an astronomy theme in her attacks. Due to the PC-98/Windows canon split, there may be inconsistencies like this between them, although attempts could be made to fit them together (like saying that she trained under Mima after seeing the shooting stars).
- It is unknown how Marisa got her home in the forest of magic, but she tells Tenshi Hinanawi that her "house wasn't built for earthquakes", and says in her Scarlet Weather Rhapsody ending that if her house is destroyed, she can always build a new one. So there doesn't seem to be anything particularly special about it, and Marisa was probably around when it was originally built. At the time of Curiosities of Lotus Asia Chapter 7, it was still new enough that Marisa referred to it as "my new house", at least in comparison to living with her parents.
- It isn't directly stated how Marisa makes a living. She does state in Strange and Bright Nature Deity Chapter 9 that she regularly goes to the Hakurei shrine to take away Reimu's youkai extermination jobs and Perfect Memento in Strict Sense implies it as well, making it a likely source of income. She's also shown a desire to sell her book The Grimoire of Marisa.  The Three Fairies of Light were her first customers to her shop, but Perfect Memento in Strict Sense implies she's had other customers since then, albeit not many. She's also a well-known thief, but is only stated to steal books, so she may not be the type to steal money.
- Marisa may be somewhat of a math genius; in Mountain of Faith she utters the line "I could recite all the digits in pi before I got there." However, considering that pi has a literally infinite number of digits which never end or repeat in any pattern (really, it's endless), it's likely just an expression to say "at this rate I'll never get there."
- Marisa holds the distinction of being one of the very few characters in any Touhou game who is known to have a living family. They've never been mentioned by name, or even within any of the game dialogues, but it is implied in Perfect Memento in Strict Sense she is the only daughter. Also according to 19th chapter of Curiosities of Lotus Asia, her father, at least, is alive and is living at the Human Village.
- In Imperishable Night, Marisa survives looking at the full moon, which should drive normal humans insane. When Alice asks if she is all right, she says that it's all right since she is insane to begin with. She might well be joking, since Reimu and Sakuya maintain their sanity looking at the full moon too. It could be that humans who are strong-willed enough can overcome that influence.
- In both Mountain of Faith and Subterranean Animism, Marisa lacks her signature bomb move, Master Spark. She regains her Master Spark as a bomb in the following game Undefined Fantastic Object.
- Marisa often refers to herself as "just an ordinary witch". This is often her character title in the games (i.e. Imperishable Night). Deneb the witch of the Ogre Battle games refers to herself in a similar, yet opposite manner: "I am a witch, but not just an ordinary witch!" She appears to make a reference to this in Perfect Cherry Blossom's third stage, when questioning whether or not Alice is an ordinary human.
- In Touhou Hisoutensoku one of her alternative color palettes gives Marisa a blue attire and red hair similar to the purple attire she wore in the PC-98 era (the colors match specifically to her attire color and hair color in Story of Eastern Wonderland). Another alternate color resembles Ellen from Phantasmagoria of Dim.Dream. There is also another palette that gives her a purple attire and purple hair, somewhat resembling Patchouli.
- Excluding the fighting spin-offs, Double Spoiler, and Fairy Wars, Marisa's face has appeared on all of the Windows game icons so far. This includes Shoot the Bullet, in which she doesn't technically appear.
- Marisa was first seen using a wand in Story of Eastern Wonderland, second time in Phantasmagoria of Dim.Dream, and third time in Lotus Land Story. The fourth time seen with a wand was in Undefined Fantastic Object and so far the only windows game she is seen with one.
- Marisa seems knowledgeable about species not native to the Japanese archipelago such as the beaver in Chapter 4 of Wild and Horned Hermit and the rafflesia in Chapter 14 of Oriental Sacred Place.
- Along with Yumemi Okazaki and Soga no Tojiko, Marisa is one of the three Touhou characters to officially curse in-game.
- She is known for the memorial "First to Use the Spell Card System™" in the history of shooting games.
- She is also the first official Windows boss of the Touhou series.
- Her ability, "manipulation of darkness," sounds quite strong, yet she is only a poor stage 1 boss.
- She is usually drawn with her arms spread out, claiming the pose appears to say, "The saint was crucified." Of course, this just makes her look more childish.
- Rumia's non-spell card attacks and her spell card Moon Sign "Moonlight Ray" are similar to the attacks of Mystic Square's first stage boss, Sara.
- Rumia references the phrase "人類は十進法を採用しました" (Mankind adopted the decimal system) in Marisa's scenario of Embodiment of Scarlet Devil. It comes from Hiroshi Mori's novel "誰もいなくなった ～Thirty Little Indians" (Then There Were None ~ Thirty Little Indians) from "まどろみ消去 ～Missing under the Mistletoe" (Slumber Erasing ~ Missing under the Mistletoe).
Coming closer, Fukashi and Yōko waved their hands, then Moe Nishinosono
spread her hands next to her face.
This wasn't the gesture of Man adopting the decimal system.
- The author commented this phrase was put in to show that she didn't spread her arms to the full extent like the character 十, but that she spread her ten fingers as if she'd counted to 10.
- Also, her sigil, shown on The Grimoire of Marisa depicts mistletoe.
- The Grimoire of Marisa: Foreword — "Well, if it doesn't, I'll just name it something grandiose like the Illusion Danmaku Artifact Encyclopedia and palm it off to a library for a high price, so it'd be OK either way..."
- Touhou Hisoutensoku: Marisa's Script — "Speaking of which, I wrote a book too! It's bad of me to keep borrowing books, so I'll put my book here at the library this time! How much will you pay for it?"