A New Save(Redux): Male Reader x Undertale Harem

A long time ago two races leaved peacefully and these two races were called humans and monsters, the two races were able to leave peacefully and in harmony until one day war broke out and after a short war the monsters were sealed underground by eight of the greatest wizards and the Barrier was born on that day and for centuries the Barrier had kept these "monsters" underground little did they or the humans know is that the Barrier also had some mental effects on those trapped underground as the newly titled Underground was filled with this strange lust in only a few days and that was 1,000+ plus years ago. Now cut to modern day and Y,N L,N a orphan and his best friend Frisk decided to climb the now legendary mountain to see if this was just some silly rumor or not. Now both have fallen into the Underground and must now deal with it's residents. Will they make friends, enemies, or potentially even lovers with the monsters? Only time will tell.