100+ sessions into my Tyranny of Dragons/Scales of War campaign, if you can call it that. Basically, there are evil dragons with schemes that need thwarting, but I'm making up a lot of it as we go. Player characters are 17th level.
In this session, they used a magical artifact to resurrect several slain allies. We have a house rule that resurrection magic can only be used on PCs. NPCs require an artifact or quest to bring back to life. This is a good house rule. You should use it. It makes life and death a bit more meaningful at high levels.
The artifact permanently drained a point of Constitution from the living individual that used it. So the beastmaster ranger, vengeance paladin, and arcane trickster rogue all lost a point of Con this session. That's a big deal!
Among those brought back to life were Vajra Safahr, the Blackstaff. Also: the elven queen of the High Forest. The rogue gave an amazing speech when this happened. Also: the father of the ranger, who revealed that the ranger's mother is a silver dragon. (Rescuing her is the next adventure.) Finally, the paladin of Ilmater was presented with a moral choice...would he bring back to life an enemy -- Dagult, Open Lord of Waterdeep? Dagult has been revealed as the high priest of the Cult of Tiamat...but the players only discovered this after they were responsible for his arbitrary, summary execution. So the question in front of the paladin was this: He swore an oath to Ilmater to relieve suffering. But do only the innocent deserve this? Or do the guilty deserve it as well? Yeah, heady stuff. Taking up the artifact, the paladin sacrificed a point of Con to bring a villain back to life. Dagult, now alive, was led away in chains. As reward for his moral awakening, Ilmater transformed the paladin's sword into a holy avenger.
The session ended with the PCs travelling to Arvandor, to a lost temple of the elven god of trickery (whom one of the characters might just be) guarded by the minions of Tiamat.
Next session: An ancient green dragon!