At the end of the homebrew campaign I'm running, I plan to have the characters face off against a big, scary monster. It's designed to be (almost) impervious to regular weapon attacks, but there will be various ways to either avoid or negate its attacks and 'defeat' it without killing it.
Through various choices made in the adventure so far, the party is actually well on their way to having it in fact be friendly towards them when they encounter it, though it will be dominated and/or controlled by the real enemies into trying to attack the party.
My party has proven to be relatively cautious so far. I would like to describe the creature as large and imposing, with very powerful attacks that would normally reduce anyone caught in them to very small pieces.
I'm afraid that when I describe the creature as super-powerful, my players will decide it is obviously way out of their league and (sensibly) refuse to enter the area, and miss many of the more interesting interactions they could have there. On the other hand, if I describe the creature as too wounded and weakened, it will not feel like the impressive, nail-biting end-of-adventure encounter I hope to give my players.
The players have discovered so far that the creature is a red dragon, though they don't know its age. They also know that it's being held against its will, though I don't think they realize yet how much it hates its captors.
In past encounters, they have reacted to various descriptions of enemies with realistic responses:
- Their first combat encounter, described as a small handful of goblins and gnolls eating dinner and unaware of the party, had the party sneak into position, then attack with overwhelming force.
- Their third combat encounter, where they thought that a horde of vicious beasts was about to descend on their position, had them retreat and take up defensive positions. (There was only a small horde of confused, weak, hungry creatures, but they didn't know that beforehand.)
This is my first time being a DM for this group (and in general) after being a player for many years, so I'm not sure whether the players have a feel for my 'DM'ing style' yet. During our session 0 I did promise not to maliciously put them in unwinnable situations, but I also promised to play the enemies as intelligent and as realistic as I could. So far this has meant using formations and running for help when losing a fight.
The party's caution so far is warranted by the situation. They are performing a raid behind enemy lines; just a three man party raiding the enemy HQ. They know that if they allow the alarm to be raised, which so far they have cleverly managed to avoid, things will get much harder for them. However, the captured red dragon is the enemy army's secret, war-winning superweapon that they have been tasked to disable, so unless they deal with it in some way, they cannot fulfill their assigned task.
How do I make it clear that, while dangerous, they have a multitude of options to deal with the creature?
Note: we're using D&D 5E, though I imagine this question could be applied across various systems.