I'm planning a new campaign where the villain will force the party to do his bidding, starting from level 3.
The opening will be an encounter with the villain, where he will "ask" them to do not-so-nice things. A good-natured (or even neutral) predictably will refuse to do so, because it involves a massacre of innocent village, for instance.
I want to intimidate them into submission, simply by showing how great the difference in strength between them and this villain, but not kill them. This villain stat should stay the same across every encounter, but slowly become beatable later. Think of it like a Darth Vader, I guess?
I will be using 5e, and this is part where I believe the problem is: the bounded accuracy means that you can't really show how great the power difference is. I mean, the players having a +4/5 attack bonus vs the villain having +7/8 will still allow them to think "well, we are 5 people, we can still try". Ramping up the AC has its limits.
At first, I was planning to "reveal" the attack bonus, "okay, so that's a 7 plus 8. I believe that's a hit?" to freak them out, but I have doubt that it will deliver the message. A very damaging spell/ability may freak them out alright, but at level 3, I fear killing them out outright (I almost always roll in open and never fudge an open roll)
Is there a way for me to accomplish this without railroading them into the choice? Or is 5e the wrong system to do this?