The one, that takes the 1st place on the list, of being the most scariest Character by Silent (and causing the most fear in the protagonist) in Fierce Forces, is indeed the Destroyed Clone... Salvage Sonic "Gory-Up!" (Yes, he was even as a hint in the poll art)

Fun Facts:

~ Salvage Sonic "Gory-Up!" is not only an Important Antagonist in FNaS: FF "II!" fancomic, but also the Main Antagonist of NFaS: FF "H!&H!"

Showing, that HE is the most feared Character in Five Nights at Sonic's: Fierce Forces series.
This even caused for the Destroyed Clone to appear in Silent's "Player-On!" ordinary dreams (Nightmare State is not required to make him appear) As if...

He was moving from his Virtual World to hers Actual World, when Silent "Player-On!" stops playing Fierce Forces game and go to sleep to take a break.

~ In the upcoming "Creepypasta Sonic" Comic, he'll be featured as that most creepy one from the rest of the blue blur clones, including some other secrets...

Also:

~ Shadow Sonic "Midnight-Up!" is from FDaS: FF "AA!!" fangame.

~ Both Characters are normally from the fancomic "Imagine It!", but they also are from their prospective future fangames.