What happens when a reinforced Despolier of Souls is killed? It’s a 10/4, and then when it dies, it respawns in play as a 5/2. What happens to the second Despoiler of Souls? Is it lost, or does it go to the graveyard?
I’d always assumed that when a reinforced creature is killed it counts as a single creature, so you can imagine my suprise the other day when I killed a reinforced Akoum Firebird (16/16), it died, my opponent made a red match4, and BOTH Akoum Firebirds were returned to play!
Mmmm inconsistencies. Nomnomnomnom
It’s possible you needed twice as much mana for despoiler though and didn’t have enough.
When the creature is summoned out, it is treated as one creature. Despoiler’s ability triggers while it is still on the battlefield so it triggers once, bringing back one unbuffed copy of Despoiler. The other copy goes into the graveyard. You can test this by using Raise Dead to return the other copy back onto the battlefield to reinforce your Despoiler (or Dark Petition as long as you have less than 3 creatures out).
Once it enters the graveyard it splits into its component cards. Once again you can test this with Raise Dead or two copies of Dark Petition. Akoum’s ability is active when it is in the graveyard so both copies can trigger to return as a resurrected Firebird.
Oh, wait… sometimes the game plays the ‘creature death’ sound multiple times… does it do this with reinforced creatures to tell you how many cards are going to the graveyard?
Wow. Never thought of this. And I always wondered about those extra screams .
In my experience, a reinforced Despoiler of Souls always comes back as a 5/3 when it’s using its ability.
However, Liliana has the ability to bring the last 3 creatures which died back to the battlefield. So, in that case, the separate screams you hear might be relevant.
At present, I have all of the sound turned completely off on my devices because I can’t stand the loud noise it makes when opening packs of cards.
I wish I could turn the screen off because I can’t stand the sight of the cards I get. 
I tried this too, but this seems to be the only sound that plays when you turn off music and sound in the settings menu. I have to turn the volume all the way down to avoid those sounds. They even play while I’m playing a podcast or music in the background. >:(