ALPHA and OMEGA by DEMOUR402 is one of the ones I remember most prominently. You should check out their other works too. Reborn from Omega is the sequel to that one and features an older more mature Marisa :D Too bad it's so short :(
Has nobody thought about just asking Yukari to let them back out?
when you plan to conquer the other world, and you're on one woman army level, I dont think so. Also there are several theories about yukari creating gensokyo for trapping the storngest and most dangerous youkais there
Is but a step that will lead us to the world we originally seek, one that we should fight for.... and return to the outside world!Namely...To take down the Great Hakurei Border...In the end, this country is but Toyosatomimi-sama's cradle.To take control of the Hakurei Miko