Traveling Through the World of Collapsing Iron, I Developed the Toilet Man Game

The protagonist loved toilet people very much in his previous life, but... Because of an accident, the protagonist traveled to the world of Honkai Star Railway, but the protagonist who traveled through time was just an ordinary person! It wasn't until the age of eighteen that the protagonist finally awakened to his own system! Then the task of the system is to let the protagonist develop a game by himself, so... The protagonist chose the toilet person he loved most in his previous life without any hesitation!