>Remnants of Orks on Kronus de-evolved into Beast Snaggas - Space Savage Orcs basically, a relatively newly introduced subfaction of Orks who are generally disliked for their models
>Gorgutz comes back to Kronus to finish what he started and unites them into his WAAAGH which starts to overwhelm Imperial defenses
>In response Blood Ravens send their 10th Company with Cyrus, now a Captain
>First SM missions are playing as him and using mostly Phobos units and Scouts fighting against Orks
>For mysterious reasons Admech is here as well
>Suddenly Necrons!
>Turns out Admech unburied and reactivated Necrons we buried as Thule in Dark Crusade by blowing them up
>Cyrus dies Thule style to this unexpected enemy
>Jonah Orion with Gabriel/Captain Hairgel arrive to avenge him. Jonah - a higher ranking Librarian - is a second commander type for Marines. Gabriel/Hairgel is third and a more generic melee brawler/tank
>In some dlc it turns out it was Chaos plot along
This is what I predict
Also Cyrus clearly dies in trailer, there are no time travel shenanigans. Entire trailer is simply in intentionally incorrect order, but you can see him fighting still in helmet at first, dueling that spider Necron, then getting thrown on ground without a helmet, but managing to kill his enemy with pistol shot. Then he tries to fight Chronomancer, but Necron functionally teleports behind him and kills Cyrus. Jonah then is leading funeral and Cyrus is cremated. This is why it's hardly a huge spoiler, he dies early in campaign as well.