Blizzard Celebrates 'Diablo' 20th Anniversary By Hosting In-Game Events In 'Overwatch,' 'World Of Warcraft,' 'Heroes Of The Storm,' 'Hearthstone,' & 'StarCraft II'

December 31, 2016, marks the 20th anniversary of the game that started it all: Blizzard's "Diablo" series. To commemorate this glorious event in gaming history, Blizzard is hosting in-game events for its current active titles. This includes "Overwatch," "World of Warcraft," "Heroes of the Storm," "StarCraft II," "Hearthstone."

The special event for the Lord of Terror is called "The Darkening of Tristram" in "Diablo III: Reaper of Souls," the biggest event in all current active titles of Blizzard. Players will be able to return to the "reimagined" version of cathedral dungeon in the original game around January, according to GameSpot. Players should also expect to find items from the original making their comeback. This is a tribute after all.

To celebrate our 20th, The Darkening of Tristram anniversary event is coming to Diablo III. What a curious portal… #BlizzCon pic.twitter.com/bjEVsKvHLf

— Diablo (@Diablo) November 5, 2016

Meanwhile, "Heroes of the Storm" will be receiving a new brawl map based on the "Battle of the High Heavens." According to SlashGear, this is a fairly significant portion of story of "Diablo III," but Blizzard did not give out noteworthy details except the game is "hectic." However, if players do complete the new brawl map, all three, then they will be able to get a brand new "Diablo-themed" profile portrait.

While players will have to tackle a new map in "Heroes of the Storm," "World of Warcraft" players could have an interesting but mostly mysterious game on their hands. Polygon reported that Blizzard only gave out tremendously sparse details, which reads: "Strange things are afoot in the world of Azeroth as denizens of Sanctuary cross over into an unfamiliar world." Perhaps, players get to see an foray of characters crossing over from the "Diablo world of Sanctuary."

The digital card game "Hearthstone," on the other hand, an unknown hooded stranger with a grim deck in his hands joins the new Tavern Brawl where players will have to uncover the secrets of the dark wanderer.

"Overwatch" and "StarCraft II" seems to be receiving the least amount of "Diablo" game content compared with Blizzard's earlier-mentioned titles. "StarCraft II" gets a "Diablo-themed" worker portrait, while "Overwatch" players will be able to unlock "Diablo-themed" sprays that can splatter all over the game's map.

Blizzard also teased that more "Diablo" game content will come. Plus, although there is no guarantee, a 4th installment of the "Diablo" series might be on its way as Blizzard has been recruiting for a new unannounced "Diablo" project.

When the exact date these promotions will commence hasn't been revealed yet by Blizzard but it is safe to assume that it might begin on the day the first "Diablo" series was launched, Dec. 31.