The idea is that certain people can accidently create portals when in their deepest state of sorrow. Once they begin to enter though, the chances of leaving are slim. Once you've gone thrpugh completely, your not you. Your gone forever and a replica replaces you. They act exactly like you save for the sorrow. Sorrow for the duplicate is more humorous than upseting as well.
A little info and some concept art for a story I'm creating.