Dauntless is an up-to-four-player co-op action role-playing game. It takes place in a shattered group of floating, post-cataclysmic islands. You are Slayers whose only reason for being is to take down world-eating Behemoths. The press release hints that it's a roguelike (meaning that it has procedurally generated environments and random encounters), but avoids using any of those specific terms.
The cinematic trailer and screenshots below reveal a dark world of big beasts. While it's not a gameplay trailer, it hints at the idea of party members splitting up to track these beasts down, then firing off flares or fireworks to call the other players to their location on the map. Most of the characters' personality looks steeped into their weapons and armor. I mean, one dude needlessly rocket jumps off a cliff with his JRPG-sized warhammer, so that's cool.
According to Jesse Houston, co-founder and President at Phoenix Labs, "We’ve taken inspiration from games like Dark Souls, Monster Hunter, and World of Warcraft," in the making of Dauntless. The rest of Houston's team is made up of folks hailing from BioWare, Riot Games, and other studios.
Dauntless will be free to play on PC sometime in 2017. But with it being free to play, it's fair to expect that Dauntless will make its development dollars back via in-game purchases.