ok, here they are. starting with Phantom Cupcake

Phantom Cupcake:find them all when the fire starts to appear at the edges of your screen. the fire will steadily spread over your screen. they always spawn in the same areas, and the cupcake will kill you if you fail to collect them all. if you collect them all, the AI of all of the FNaF 1 Characters will be lowered by 1.

Glitched Augmented Freddy: He will be in the front of the office. around every 45 Seconds, he will make the haywire noise, which you have to look away quickly, or he will temporarily either disable your cameras for 3 seconds, take all your fazcoins, allow you to either gain or lose 5% power, or will disable your mask for 5 seconds.

and Lastly, the titular Character,
T H E D E V I L H I M S E L F . . .

Satan: will cause hallucinations of characters that did not get that mechanic(I.E. FNaF 1 Bonnie in FNaF 1, of Nightmare Freddy behind you, etc etcetera) and will increase the amount of hallucinations until it seems like full-20 mode, when in reality, it's still only one higher than it was before(but you won't get to know which.

if you react to something fake, he will kill you.