D&D 5E When an entire campaign comes down to one roll

[DND_Reborn]

How does the dragon know what level the pcs are? Was that an arrow of dragon slaying that just missed?
As a DM I think I killed a pc who ticked off the dragon in this hardcover. Attacking a dragon is mistake. If you come out with it with your lives, your dm is being nice.

Well, whether the arrow missed or hit, and how much damage it did that being the case, would give the dragon an idea. If they had strong magical items, such as an arrow of slaying, that hit it would have also keyed it into the relative strength. Since its fear worked on most of them, that is also an indicator, along with them pleading for their lives...

 

[Panda-s1]

dammit, the post reminded me of this: DM of the Rings CXLI:The Moment of Truth - Twenty Sided except I didn't think this was the sort of thing that actually happens irl lol

 

[Sacrosanct]

Well, whether the arrow missed or hit, and how much damage it did that being the case, would give the dragon an idea. If they had strong magical items, such as an arrow of slaying, that hit it would have also keyed it into the relative strength. Since its fear worked on most of them, that is also an indicator, along with them pleading for their lives...

And the fact that a critical hit by the rogue still only did 11 points of damage, and a flick of its claw was enough to drop most of us

 

[Maxperson]

while a poor choice, and we told her to stop, that wasn’t really an action that supports “the players deserved to die because they made bad choices” as claimed above. Or does a person deserve to die any time they irritate someone else in your eyes?

You are correct that that decision does not warrant death. It does however play into what followed it. That bad decision was a modifier to the 1 that followed, and then added to that 1 when the drow decided to try and kill the dragon. Then add second 1 to the two bad decisions and the 1 and you have a recipe for a TPK.

 

[LordEntrails]

There is no one answer or true way this should have played out. Claiming the dragon should have reacted this way or that, is really not useful. Saying how you would have ruled it had you been the DM is can be part of a useful discussion. There are a thousand ways to play a lawful good dragon, all of them equally valid.