The problem with tails is that most of them are merely a butt accessory. You need special training and hours of dedication to repeatably use a tail the way you want.

Drakkonkin [Kobolds, Dragonborn, and varying sizes of Dragon] only use their tails as counterweights or self-expression. They can, if they think about it, lash their tail at a foe. After all, they've spent most of their time avoiding the circumstances where their tails get in the way.

Tieflings also spend most of their time trying to keep their tails from being a problem. Purposely making their tail a problem is either an asshole move or a sign of dedication or both.

As for the minions, I kind of want to take the lazy path and say they were hired by Malforence. Because I have one overly complicated storyline in residence in my head, and there's no room for anything else.