@iskelets8 I believe the MC unconsciously love his step sis too I believe he is using what’s called sublimation it’s a defense mechanism where someone who has unacceptable impulses change it into something more acceptable even productive an example is a hyper aggressive person decide to be a professional MMA fighter beating random people is unacceptable but beating people in national TV is.
In his case he loves his step sister romantically but due to it being not acceptable he instead poured all his desire in making the LN that’s this is also why he doesn’t know what to do when confronted with his step sister’s love due to the fact then when people’s defense mechanisms are confronted or stop working the experience great anxiety and distress and is causing the mental damage the MC is experiencing.
This series is surprisingly high IQ similar to rick and morty only few and well educated people will understand the story.