At one point in development, ZUN intended to add a third playable character, Rin Satsuki; however, she was dropped from the final game due to time constraints. The sole remnants of her are two strings of text in the game's code, which reveal that she would've wielded Flower Sign (Type A) and Flower Sign (Type B) Spell Cards.

For years, fans speculated that Satsuki's official design was a circle cut illustration showcased at Comiket 62 in 2002. However, in 2014, doujin artist Rian Sakuragi revealed on Twitter that the artwork was simply a standard "poster girl" with no relation to Embodiment of Scarlet Devil. Nine years later, ZUN revealed in a talk at Tokai High School that he did indeed draft a design for Satsuki, though it was never publicly shown off.

In Marisa's storyline, Remilia Scarlet responds to her question "How many people's blood have you sucked until now?" with the taunting counter-question "Can you remember the number of times you've eaten bread?" Marisa then responds that she's only done so thirteen times due to her preference for Japanese food. This parodies a similar exchange between William A. Zeppeli and Dio Brando in the 1987 manga JoJo's Bizarre Adventure: Phantom Blood.