You need Minion Masters(Free to Play)
https://store.steampowered.com/app/489520/Minion_Masters/
New Voidborne Onslaught DLC is available for FREE for this week only until Friday the 15th!
https://store.steampowered.com/app/1033840/Minion_Masters__Voidborne_Onslaught/
This pack is worth $15 and comes with the following:
Animated Voidborne Onslaught Avatar
* Animated Voidborne Onslaught Emote
* 3x Colossus
* 5x Succubus
* 20x Rammer
* 40x Nether Bat
* 40x Morgrul's Ragers
* 5x Power Tokens