This plot is actually retarded.
They apparently spent weeks working on this scheme of farming monsters to feed the A-rank monster, all for the sake of killing some random girl; who's only coming to this area because the main character just happened to be traveling there
This author is working...
I know it won't happen, but it would be amazing if this masseuse was just like "wassup bro. You should probably take those pity gifts back. The whore you married has been trying to get me to sleep with her for weeks."