They just came out today.
Corruptions come in a bunch of different flavours, with 11 different monster types to choose from. They are meant for players to actually emulate monsters, but you risk losing your characters, and have some poorly explained reasons. There are three "Corruption" stages, and nefarious actions can cause you to gain another stage, which vary by corruption. For example, Ghouls can advance it by eating innocent people. At stage 3, you lose your character, no exceptions.
One is that you want to become a Lich, and slowly turn undead. At stage 3 of Corruption, you successfully become a Lich by dying and having allies bring you back with a Miracle or Wish. And you have to give up your character, because you are now Evil and Undead.
Another is the Promethean, which turns you into a Construct. At stage 3, you have so little living material for your soul to cling to, it simply disconnects from your body. But your body is still alive, albeit a mindless, true Neutral Construct. Why can't you just roleplay a mech that just belongs to the party, like some sort of unholy abomination of a party mascot? With no mind, it just goes "Beep boop, kill everything" like its some sort of Terminator.
It just doesn't make sense, since in this same book is a complete rewrite of the insanity system, explicitly so that insanity is no longer an end of a character. It also implements a sanity system for Horror oriented games. Things can deal sanity damage and stuff.