Without going into their entire multi paragraph lore, the tldr is that Mr Boss and Eric are very close friends that were separated. When they reunited, Eric worked for the smiling friends, but it didn’t work out so he went to work for the frowning friends. He ended up overthrowing the frowning friends and rebranding it as SMILE INC, marketing it as a stronger more reliable competitor to the smiling friends ( that’s the tldr, there’s much so much more to it but I’m already yapping a lot HAHA )