Flandre Scarlet

In Embodiment of Scarlet Devil, she is described as being quite strange and eccentric, which makes it difficult for others to understand her. She's also described as being "normally docile" and generally pleasant to be around, but somewhat of a loose cannon if left unwatched. In Bohemian Archive in Japanese Red, it's suggested that she isn't very good at talking to other people, though she can get rather sassy and uppity when talking with her sister. Her friendship toward humans is very low. Until the time when she met either Marisa Kirisame or Reimu Hakurei in Embodiment of Scarlet Devil, she claimed to not have seen any humans other than when they were prepared for a meal, although it's left vague as to whether that was her idea of a dark joke.

In Foul Detective Satori, her attitude was particularly impolite and informal, speaking in a very casual tone and generally doing as she wished without consideration of consequences, although she stopped short of seriously injuring anyone.

In Sunken Fossil World, she left the grounds of the Mansion for an extended period of time of her own accord to fight Yuuma Toutetsu, marking her first major departure from the grounds of the Mansion since her introduction. She appeared to only care about "destroying the indestructible" when facing off against Yuuma, although she did display a willingness to work with Okina Matara, insofar as Okina let her have some fun.