Two people in Scripture are referred to as “Son of Perdition”:
Judas Iscariot
&
The Little Horn that rises (A/C)
What separates him and his false prophet from all the rest of the damned?
(Two people in Scripture are referred to as “Son of Perdition”:)
Yes. And only those two.
I always found this passage significant regarding the first son of perdition:
https://www.biblegateway.com/passage/?search=John+13%3A27&version=KJ21
The Antichrist and the False Prophet were both seized while still alive, too.
Judas of course was dead not long afterwards.