What if Tev could regain the sort of power he had serving under his dad (but with his free will and no master to serve minus himself), but he had to kill a friend of his. Would he do it?

He’d probably ask all sorts of questions like “does it count if they’re willing to do it” and “could he bring them back?” but it’s likely that he wouldn’t if those conditions couldn’t be met. He’s already growing in power and its not like he doesn’t have the time to wait until he’s reached that sort of power on his own anyway.

Of course if he can find a willing participant, then sure