Based on what I’ve seen of Grogar, he DOES feel a lot like an MLP version of Thanos.

• Yeah, I know the characters’ relationship don’t match the ones in the movie but just go with it. *
   
  Twilight: I told you, you die for that.
   
  Twilight blasts him in the chest again.
   
  Grogar: You should’ve…
   
  Twilight leans in closer.
   
  Grogar: You should’ve aimed for the head.
   
  Grogar flicks his bell.
   
  Twilight: NOO!!
   
  Everything goes white and Grogar finds himself in a strange place where he meets up with Bray.
   
  Bray: Did you do it?
   
  Grogar: Yes.
   
  Bray: What did it cost?
   
  Grogar: Everything.
   
  Back in Equestria Grogar stared at the bell as it turned to dust.
   
  Twilight: What di you do? …What did you do?!
   
  Grogar stomps his hoof and teleports away. Twilight just stands there in shock.
   
  Rainbow Dash: Where did he go? Twilight.
   
  Twilight is unable to answer.
   
  Rainbow Dash: Where did he go?
   
  Scootaloo: Dashy…
   
  Rainbow Dash turns to her only for the filly to turn to dust. She kicks at the dust in disbelieve. Again Twilight can give no words.
   
  All across Equestria more fall to dust. Lead some like Tempest to look on helpless.
   
  Starlight goes to pick Trixie off the ground.
   
  Starlight: Up Trixie, up. This is no time to die…
   
  Trixie: Falls back down confused to the dust in her hands and Starlight gone from sight.
   
  Trixie: No…
   
  Meanwhile, Spike reaches out to Rarity with final words as he too slowly turns to dust.
   
  Spike: I will always love you…
   
  Rarity: Oh, no… no… no… no… Spike… no…
   
  At the same time, Fluttershy still gripping Discord’s cold corpse leaning back upon feeling her legs gone and as the dust fully consumes her she gives one final tear,
   
  Cheese slowly picks himself up thinking he’s survived only for the dust to claim another. Too late to see Pinkie Pie walks over his dust screaming his name. Trixie hearing more sorrow can’t hold back the tears.
   
  In Tartarus, the student six slowly pick themselves up. Ocellus looks up.
   
  Ocellus: Something is happening…
   
  She vanishes before she could finish. Sandbar and Yuna quickly follow her. Smolder looks on in shock.
   
  Gallus: Steady Smolder…
   
  Smolder: Oh no…
   
  Despite Gallus’ words, Smolder is taken as well. Gallus turns away and looks toward Cozy Glow.
   
  Cozy Glow: Gallus… there was no other way.
   
  Cozy Glow is dusted shortly after her words. Gallus tries to figure out what the filly meant but is halted in his thoughts be another’s words.
   
  Silverstream: Gallus… I don’t feel so good.
   
  Gallus rushes over to her.
   
  Gallus: You’re alright.
   
  Silverstream: I don’t… I don’t know what happening… I don’t know… Iididid…
   
  Silverstream’s words become mumbled as she turned to dust.
   
  Silverstream: I don’t want to go… I don’t want to go… Gallus, please… I don’t want to go! I don’t want to go!
   
  She falls to the ground and just stares at Gallus.
   
  Silverstream: Gallus… I… lov…
   
  Her words are stopped as the dust fully claim her. Gallus struggles with the dust endless with Chrysalis’s words being the only thing that brings him back to reality.
   
  Chrysalis: He did it.
   
  Gallus turns away from her hiding the shame in his face.
   
  Back in Equestria what remains of the mane six gather around Discord. All are silent in either denial or disbelieve. Pinkie Pie giving the only words she can.
   
  Pinkie Pie: What is this? What is happening?
   
  However, despite all of these creatures reasoning some sort of possible wrongness in dusting Rainbow Dash is the only one that can finally see the truth and destroy her denial in two words that bring only horror to her face.
   
  Rainbow Dash: Oh god…
   
  Somewhere in a far off land, Grogar walks through an opening to the sight of a castle in the distance. Everything is silent for him yet against all he lost and all the pain he suffered he can only smile.