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Maybe a demon invasion threatening to end all life is exactly what World of Warcraft needed.

Activision Blizzard revealed in its earnings report for the third quarter of the financial year 2016 that the latest expansion for the massively multiplayer online role-playing game, Legion, sold 3.3 million copies on its first day, August 30. According to Activision Blizzard, this matches records set by previous expansions and ranks among the fastest-selling PC games ever.

Activision Blizzard no longer reports subscription numbers for its flagship MMO, but it did note that active monthly users for WoW have have increased 30 percent quarter-over-quarter. At its height in 2010, WoW had 12 million subscribers, but that number dipped to a low of 5.5 million in 2015 before the publisher stopped giving out those numbers.

World of Warcraft expansions always bring a rise in subscriptions, since the new material gives lapsed players a reason to come. The trick is getting them to stay. The expansion before Legion, Warlords of Draenor, initially increased the player base from 7 million players to 10 million, but those adventurers slowly retreated again from the MMO.

However, Legion might be compelling enough to entice players to stay around. Our own review praised the expansion as the games best ever thanks to the more flexible and convenient questing and progression systems, while a new emphasis on 5-player content gives friends a way to earn good loot without having to join larger party sizes.