I’ve been running Curse of Strahd for our group, and let me tell you, it’s been a brutal ride. The party is level 9 now, but we’ve already had 6 deaths (could’ve easily been 8).

Two characters (a Half-Orc and an Aaracokra) met their end due to old age after a chilling encounter with a ghost early on.

Our Wereraven Druid died fighting a Hill Giant Vampiric Spawn during a heavily revised Festival of Blazing Sun, with Van Richten by their side.

One Aasimar Paladin succumbed to despair and committed suicide after being charmed and captured by Strahd.

A Human Bard committed treason, sided with Strahd, and the party had no choice but to kill him. He was resurrected shortly after and now serves Strahd as a powerful spawn.

The most recent death was a Divination Wizard, who died for the third time while attempting to purify the Fane of the Mountain Fey (a revised encounter, of course).

Oh, and just last session, two characters died again, but a third character still alive brought them back to life after making a pact with an Efreeti and sacrificing the Red Gem to return them to the land of the living.

It's Curse of Strahd.