@Finagle070  
I was wondering if somebody was going to figure it out. Congrates

That’s the seal of King Bael from the Ars Goetia, with O’s replacing the letters in his name surrounding the symbol.
 
Bael is first king of Hell with estates in the east. He has three heads: a toad, a man, and a cat. He also speaks in a raucous, but well formed voice, and commands 66 legions. Bael teaches the art of invisibility.
 

called it on the thralls

@Background Pony #5FA2  
Discord didn’t carve magical sigils on the mane six either. And no, Discord’s magic wasn’t broken through willpower, but through Twilight’s memory spell restoring their original personalities.
 
Plus, if we want to add wild speculation on how the FiM world works, it’s very unlikely Discord would kill in any case since he can’t have much fun out of a corpse, whereas a malevolent vampire not only gets distractions, faux-willing hostages, and free snacks from them.
 
Also you’re comparing Discord’s chaos magic, to a blood magic seal which by nature relies on structured rules…aka ORDER. Basically you’re comparing two types of magic which are probably oil and water to each other and thus would probably work by different rules and limitations.

@Spiritus Arcane  
Cept there is no way they would kill themselves.
 
Remember the last time someone subverted a pony’s will? Discord’s magic got broken by willpower. Pretty sure the impulse to not slit your own throat would break this fucker’s spell like frail china.
 
This is an asspull explanation.

Yeah. its not like people would LOOK for that kinda shit in a magical world where……..
 
You know what, no. This concepts FAILS to work. Discord, one of the most pwoerful beings in the series, was not able to truly subvert another’s will. His magic got broken by willpower alone, if some help giving it a boost by Twilight.
 
So how the fuck would these ponies follow till death without theri willpower breaking the spell first? No way this is even in the ballpark as Discord. Fuck, its all the way at the paddleball set in the diner five miles away.

Like throwing hot pockets at nerds…