Sombra or Grogar.

Calling it now. Starlight is a descendant of the season 7 big bad and the characters saying towards the end that it could hurt someone was foreshadowing. Either Trixie or sunburst are gonna get hurt or cursed in someway, causing starlight to go super saiyan and defeat the villain or leave ponyville to find a cure. Maybe both.

@Esteban  
Not really a twitter whore. So I can’t say if this is true. And If I remember correctly, they didn’t show the horn on camera. So it’s an obvious enigma if it’s indeed a one shot thing. But the thought that this comic would only tie in in the show is a suspecion

@Ponynstuff320 (Toon-n-crossover  
Wasn’t Pony of shadows just a Visual gag that Haber put in CastleMania for finale joke?

@Esteban  
Well, it is teased that the pony of shadows will return. So Shadow Lock would be no doubt that entity.

@RIG  
Hmm, not neccessary. They may actually pull out the same thing as in S1 premiere. After that evil Alicorn appears and terrorise Equestria for two parts, we could have him be defeated like Nightmare Moon and have him transform into his old self - Shadow Lock and have him become a reccuring character like we have Luna. After all this comic made a big deal out of Shadow Lock transfomring into the main villain. He could hang out in Twilights castle like Starlight. Every season, her castle would be filled with the single main reformed villain. Hasbro could be playing that long game since they don’t think about wrapping the G4 anytime soon.

SCORPAN IS GO

Uh… Maybe it’s just me, but this sounds like rubbish until now…

Neighdolf Haytler.

the only thing the show will use is that changeling like thing (which idw knew before hand from season 7 scripts), this guy will not appear on the show, not even a mention.

Does this mean a family heirloom episode?
 

@PonyPon  
I suppose, I haven’t read this particular comic so I don’t know what goes on in it.

@Background Pony #C737
 
…I don’t get it.

Well we do have two parent episodes.
 
@mylittleyuri  
It’s a common symbol.
 
Sure it means nothing.

why does he have twilight’s cutie mark on him

This doesn’t necessarily mean that Shadow Lock and his ancestor will actually show up in season 7… It just means that this storyline tied into the “family” and “legacy” themes that season 7 is doing.

@Background Pony #C737  
Woah
 
Did. Not see that coming

Family and legacy?