Greed Army

1 - Greed Army [link] (here)
2 - Apple Soldiers [link]
3 - Wildfire Legions [link]
4 - Winged Furies [link]
5 - Coming home [link]

STORY TIME!
When Equestria's magic had corrupted only the Earth ponies, least reliant on their powers, had remained mostly sane. The pegasus and unicorn ponies had torn apart the villages and war soon broke out across the land.

Unmissable on empty battle fields was the Greed Army.

Corrupted, the unicorn Rarity had fallen into a dream ruled by greed. Eager to please, and soon falling into the same dream with his beloved, the dragon Spike had joined her. Together the pair scoured villages and houses, later camps and battleground, forever searching for anything they wanted, and they wanted everything.

Growing large on the gluttony but starved by his greed-ridden mistress, Spike grew and contorted into a foreboding steed. Atop her armoured fashion accessory Rarity lusted for more and the pair's hoard grew until Diamond dogs and other dragons joined their ranks, begging for the pair's scraps and hoping for a chance to steal more.

That is how the Greed Army was born.

If there's anything that we've learnt about the MLP universe it's that selfish emotions will physically change you.

So basically recall Discorded Rarity and greedy Spike. Here's their battle form!

Rarity's not looking so good right now because these are early days. Lots of success and Spike would be a much fancier battle dragon and Rarity's hair would be in tip-top condition (thanks to the servants pampering her in her own personal palace miles behind the battle front).

I was going to go over the armour bit by bit but I'll let you work out what's necessary and what's decoration.

(I guess Spike's other foreleg is lifted out to the side or something.)

Original sketch here: [link]