Blizzard celebrates Diablo's 20th birthday via in-game events

December 31 is the 20th anniversary of the release of the first Diablo, and to mark this most auspicious of occasions Blizzard has announced a series of limited-time in-game events across a variety of their current titles. A brief outline of what you can expect can be found below:

Diablo III: Recapture the feeling of your first play through of the original Diablo with The Darkening of Tristram tribute event. Venture through a reimagined version of the original cathedral in Diablo III and keep an eye out for some familiar items.

Heroes of the Storm: The battle for the High Heavens continues, and a new Diablo-themed portrait is up for grabs! Can you emerge victorious on this hectic new brawl map?

Hearthstone: In this Tavern Brawl, a hooded stranger awaits, holding a grim deck in his hands. Will you unravel the secrets surrounding this dark wanderer?

Overwatch: Bring the battle for Sanctuary into the fight for the future with in-game sprays representing your favorite Diablo III classes—along with a new player icon modeled after the Lord of Terror!

StarCraft II: Put the Lord of Terror to work for you with a Diablo-themed worker portrait.

World of Warcraft: Strange things are afoot in the world of Azeroth as denizens of Sanctuary cross over into an unfamiliar world.