Warning: Spoilers Off applies to these pages. Proceed at your own risk.
First of all, the teaser trailer. Showing the one Horseman we haven't yet been able to play as: Strife. He saunters casually into an enormous hall filled with demons on either side and stands up to a humongous three-headed demon. Just as the demons move in to attack, he draws Mercy and Redemption, shots ringing out as the scene cuts to black.
The "Not Alone" trailer shows us the full version of the above scene. Strife can go toe-to-toe with Dante and Cayde-6 in the wisecracking and gunslinging departments.
War's trailer is a combination of gameplay and the massive Rider of the Red Horse slowly rising up from a crouching position, Chaoseater at the ready, to the sound of dark, rumbling music. Fitting welcome back to the Horseman who first introduced us to the franchise.
Strife displays some badass tricks with his revolvers in his trailer: Gun Twirling before shooting both, fanning the hammer of one gun while still holding the other, then bringing both up in opposite directions to fire simultaneously. Goes to show that while War and Death may've borrowed the guns for their games, the Rider of the White Horse is in fact The Gunslinger of the Horsemen of the Apocalypse.
The cutscene of the Horsemen joining the battle of Blackstone's Keep ends with Strife slugging an even bigger demon in the face. No weapons, just one fist.
When Strife jokingly warns him not to go too nuts in his anger, lest he loses another arm, War reminds him that it took all three of the other Horsemen to restrain him and chop it off last time.
One of War's lines in the battle against their resurrected Nephilim brothers is, "We are not Nephilim. We are Horsemen!"
A little moment where Strife nonchalantly insults Samael face to face. Doubles also a funny moment. Strife was probably fed up with being Samael's errand boy killing and stealing shit for favors and was just dying to take the piss out of him. Strife pushes, nay, punches two of Samael's biggest Berserk Buttons (being interrupted and disrespected) and gets away with little more than a wordy threat and you can tell by Strife's tone he barely gave a shit about it.
Samael: You've returned. I will say, the— Strife: He called you a pissant. The Foreman. Really wasn't impressed at all. Just a head's up. Samael:(unbelievably pissed) What did you say?! Strife: Sorry, I just promised the Foreman I'd tell you what he said, right before we ripped his innards out. Anyway, continue.
How Lucifer's pawns meet their ends.
A wounded Mammon tries crawling into his magic mirror to escape, but War shatters the glass with one good stomp. Mammon's taunts about their threats meaning nothing is cut off by Strife blowing his head off.
Belial barely manages to escape his death by bargaining with the Horsemen for a way into Eden. He's all smug about Eden being their grave once they're gone, but then he freezes up.
Lucifer: Belial, you stupid beast... Your incredible failure may yet serve me... But it must be punished all the same... Endlessly. {Evil Laugh} Belial: C-curse you... deceiver!
Astarte's taunting of the Horsemen, especially after she just reanimated the corpses of the Nephilim they had to kill once, is rewarded with War splitting her in half.
Dagon tries to drag War and Strife into the water in his dying moments, but a few gunshots and explosions of water later, both Horsemen resurface. Strife's covered in gore, but otherwise okay.
A beaten Moloch reveals to the duo that Lucifer's plans are already complete, mocking them about trusting Samael and not knowing about the Animus. Cue Samael crushing his rival's head against Chaoseater's blade.
In the long run, Lucifer's schemes may prove detrimental for humanity, but Strife and War's efforts did do good: Eden, at the very least, is safe from any demonic manipulations, and Hell has lost some of its top dogs. They're also on better terms with Heaven for stopping Astarte and the Corruption (for now).
Samael is a lot better off when the game ends. Four of his rivals gone, and at least Mammon's treasure horde and Moloch's operations his for the plundering. And he technically didn't violate the Balance at all, so the Council can't convict him.
The forging of the Seven Seals in the post-credits scene, with Abaddon and Samael as witnesses for Heaven and Hell, respectively.
Angry head: Listen thus: With the forging of these Seven Seals, a great treaty shall be wrought in the name of the Balance. They who break it shall suffer the Horsemen's wrath. Wise head: Let our will be manifest within the Seals. Three from the children of Heaven... three from the dwellers below... And a final seal from our own wisdom. Reasonable head: The Council has spoken.
