Despite coming off as simple-minded, Sumomo is actually quite knowledgable of how things are done in Gensokyo and highly critical of Reimu's way of dealing with youkai. For her, this is all part of what makes Gensokyo "fun" and that's why she decided to have a little of her own fun while helping a friend draw an amusement park in the Road of Liminalty. She does not seem to get along with Aya, Momiji and the tengu of the mountains as much as he does with him, though.