Changeling

 Aggressive, deceptive, and loyal to their hive changelings are insectoid pony like creatures.

Changelings have shapeshifting magic that enables them to shift form and voice with stunning rapidity. They use this ability to fool their victims and drain their love, which they innately crave despite not needing it to survive.

Recent pony scholars have discovered that changelings are more insectoid than mammalian - hatching from eggs as larvae in collective hives. But beyond that - how their Hives work, the role of Queens in their society and breeding, how they acquire love, and how they think, are up to the imagination as any who travel to their territory will meet an almost certain demise.

Fortunately for their neighbours, their militarism and aggression mean that changelings spend far more time fighting each other than outsiders, allowing Olenia and Equestria to outmatch isolated incursions.

But all of that changed when Queen Chrysalis united the hives under one banner. Now the changelings have set their sights on neighbouring nations and their lovely inhabitants...

Racial Technology
The changeling research tree is a tree oriented on breakthrough, organization, population, and resources, providing two special units.
 * are light Changeling special forces that move quickly (6km/hr) and have decent breakthrough. They excel at fighting in cities, forests and jungles but cost a lot of support equipment to produce.
 * are recon Changeling support units that provide small bonuses to the effectiveness of troops, especially in recon.

Infiltration
The infiltration tree has two paths - one boosts general performance and the other greatly boosts infiltrator companies.