At the PC Gaming Show Firaxis' Jake Solomon gave us our first look at XCOM 2: War of the Chosen, a huge expansion that adds new enemies, environments, missions, classes and fellow resistance factions. It is due out on August 29.

The Chosen are alien heroes with distinct personalities and skillsets tasked with hunting XCOM across the world. You battle them multiple times during a campaign, and each time they grow stronger as the human vs. alien arms race escalates.

On the strategic map the Chosen will constantly try to sabotage your organisation. On the battlefield they will taunt you, referring to previous encounters. Occasionally they will even kidnap your soldiers. Jake Solomon detailed The Assassin on the PC Gaming Show stage, she's a stealthy purple close combat master. The other Chosen include a sniper called The Hunter and The Warlock.

In War of the Chosen XCOM is joined by three other resistance factions. Each have their own philosophies and fighting styles. You have to unify them to recruit them to XCOM and gain the benefits of their tech and unique personnel.

Resistance heroes are especially powerful, "the most powerful soldiers we've ever created" according to Jake Solomon. Reapers can stealth, snipe and sabotage. Skirmishers are alien defectors, and serve as extremely quick human hybrids that can perform lots of actions per turn. Templars are powerful psionic fighters who charge up their power over the course of the fight and then go full Carrie towards the end of the mission.

You can work with the other resistance factions on the strategy map, lending soldiers to help them out with missions. Once XCOM and a resistance faction become friendly enough, you can give them powerful strategic orders.

That's already quite a lot to deal with, but there's more. War of the Chosen adds lost cities, abandoned during the alien invasion. They are now full of former humans mutated by alien tech. They come at you endlessly in swarms and are drawn to the sounds of combat. They will attack XCOM and aliens, so expect some chaotic three-way fights in lost city zones.

There are many more smaller features to be detailed in future. Soldiers will be able to form bonds and pair off. There's an in-game propaganda poster generator that will let you spread the word about XCOM's achievements, and there will be a daily challenge of some description.

That's a lot of new stuff. XCOM 2's next phase could have easily been a Terror From the Deep style scenario, but I'm glad Firaxis has gone in this direction. Battling water aliens would be novel for a while, but it wouldn't do much to play with the established rhythms of an XCOM campaign. Nemesis aliens you have a persistent relationship with, and co-operative factions, are both new concepts that should meaningfully reform the game and tell new stories with XCOM's razor-sharp systems.

Check out this post for more from The PC Gaming Show at E3 2017. You can watch the show live on Twitch, and catch up on all the news from this year's show right here.