My Long Journey Living Inside The Beast

This is the story of how the protagonist has teleported somewhere into another dimension. The dimension, where the protagonist, who refers to the first-person (readers) has been teleported into, consists of strange environment. You try to figure it out on how to go back to your own dimension. Unfortunately, you are accidentally shrunk down to an ant-size by someone who has tried to steal something from where you have currently been. You feel defenseless and beg for help but no one hears your plead..... Except for the one who is trying to hunt down criminals relentlessly..... A monster has appeared before you....