Thanos returns to Fortnite -- but this time it's your squad versus his.

Fortnite Endgame LTM (limited-time mode), announced Thursday, brings Avengers: Endgame weapons and outfits to the popular battle royale game along with Thanos and his Chitauri in a race to find the six Infinity Stones.

Along with items to be found throughout the map, you can complete challenges for free rewards such as sprays, banners and the Avengers Quinjet Glider, according to the announcement by Epic Games, Fortnite's publisher.

If you've got some V-Bucks burning a hole in your virtual pocket, you can also buy a Black Widow outfit and Widow's Pack with a Widow's Bite Pickaxe and Widow's Pirouette Emote. Or you can hold out till early next week, when Epic plans to release a second outfit set.

Epic teased the Fortnite Endgame tie-in earlier in the week. On Wednesday, the Fornite Twitter account tweeted an image of a character wearing Iron Man's repulsor gloves.

This followed a teaser Tuesday of a Fortnite-ified version of Thor's magnificent ax Stormbreaker and one Monday night featuring Captain America's vibranium shield. All of the teasers touted the release date of Avengers: Endgame, April 25, so today's release wasn't exactly a surprise.

This isn't the first tie-in of the two most popular brands in the world. Last year, Thanos appeared in Fortnite as a playable character -- if you found his universe-killing Infinity Gauntlet on your map, you turned into the giant purple supervillain, complete with superpowers.

Avengers: Endgame hits movie theaters worldwide on Thursday, April 25. CNET's Abrar Al-Heeti is watching all the preceding movies in a single, insane 59-hour Marvel marathon in preparation for its release. She started on Tuesday and she's still going!

Now playing: Watch this: 24 hours into the 59-hour Marvel movie marathon

Fortnite is a massively popular multiplayer game for PCs, consoles and smartphones that has you shooting other players and building structures for cover. It went stratospheric with the addition of a battle royale gameplay mode (a la PUBG), in which 100 players duke it out on an island until one person is left standing, victorious.

Its maker, Epic Games, has since parlayed Fortnite's huge success into Epic's own game store, seeking to edge out rivals such as Steam on PC. Fortnite has also been the venue for huge online events, such as a gig by DJ Marshmello in January.

Originally published April 23.

Updates, April 24: Adds Fortnite tweet featuring Iron Man's repulsor gloves; April 25: Adds official announcement details.