Blizzard's famous Diablo series celebrates its 20th anniversary this year. To mark the occasion, Blizzard is holding in-game events not only in Diablo III, but also some of the developer's other big franchises. These include Heroes of the Storm, Hearthstone, Overwatch, StarCraft II, and World of Warcraft.

Diablo III's in-game event is called The Darkening of Tristram--it lets players run through a "reimagined" version of the cathedral from the first game. Heroes of the Storm is offering up a Diablo-themed portrait, while Hearthstone has a mysterious "hooded stranger" awaiting players.

As for Overwatch, it has some Diablo-themed sprays up for grabs, while "strange things are afoot" in World of Warcraft.

Here is a full rundown of what's happening in Blizzard's games "soon" to celebrate Diablo's 20th anniversary, with descriptions written by Blizzard;

Diablo III:
  • Recapture the feeling of your first play through of the original Diablo with The Darkening of Tristram tribute event. Venture through a re-imagined 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?

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

  • 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.

Source: GameSpot