So just what is Marisa anyway? Realistically speaking she should just be another random no-name girl from the village, yet she dishes it out right alongside the certified shrine maiden and plot armor protagonist Reimu, lives inside a forest that's so toxic she herself has developed a degree of poison resistance, and apparently even built her own house there (assuming she didn't steal that from someone else, too). Considering all other humans in Gensokyo are glorified youkai bait unless they're shrine maidens or no longer human themselves, it seems implausible that Marisa can merrily live outside the human village without getting eaten. Unless that entire stuff with Mima still plays a role, but that in turn would raise the question why Mima would have taken her in as a disciple to begin with. Is she supposed to be something like the ultimate wildcard? Or the epitomes of what humans can achieve if they actually pull through?