So I started it off with something plausible in 40k lore, Warp travel anomalies. In this case it sent them back in time 38,000 years. Across the galaxy to Reach's system. Totally plausible. They were in a Deathwatch stealth ship, probably a little smaller than the UNSC's frigates. But way better armed and protected. Their astropaths couldn't see the Astronomicon or sense the Warp. They decided to scout out the planet nearby. Their captain had no idea their location, predicting the Segmentum Obsurus.
There were three characters:
- Brother Enoch, Dark Angels Devastator Marine
- Brother Ar'nuld, Salamanders Techmarine
- Brother Otto, Blood Angels Apothecary
- Black Templar Assault Marine that was not able to make this session.
Their Thunderhawk landed in a remote area, humans running about for cover, thinking the UNSC was there for some unknown reason. They stop and question a family, Otto knowing somehow broken Hungarian, they learn that they are on Reach, its a military planet, they are at war with xenos called "the Covenant", the Imperium knows nothing of this Planet, and this is a planet lost to Humanity. They demand to see the King of the planet, so they take the man and have him help them find New Alexandria.
After a couple hours they land on the tallest building in New Alexandria, and are met by a policeman who asks for their identification. After a brief, but nonviolent exchange they are told to wait in the lobby for the Admiral. And discover small things about the UNSC, most notably they have a place called Earth that is like Terra, primitive Astartes called Spartans, and that their records are totally incorrect. The Techmarine shows him a external drive of the sum total of unclassified Imperial history. And laughs that their military proves no threat to them, the UNSC has been incredibly wary but has not attacked the twice the size of Spartan-IIs/slightly smaller than a Hunter. Seeing that they are human, but altered. They arrange to meet with Dr. Halsey and recover the location of the Covenant so they can purge the xenos so these humans will return to the Imperium.
They board the Thunderhawk, the admiral comes along with five Spartan-IIIs, and they note their armor design and size. The Techmarine surmises that it is built along completely different principles but is not derived from xeno technology. Meeting Halsey in a field they see she brought eight Spartan-IIs, infantry, and five tanks. But things go peaceably. Ar'nuld asks for a dataslate so he does not have to hand over the external drive, he somehow allows the two vastly different pieces of technology to interface and uploads the computer pad. It fills the computer as it is an extremely large file and poorly optimized. Halsey brings out Cortana to optimize and translate it, which Ar'nuld about flips his shit over, not fully realizing it is an AI, but knowing that this is tech-heresy. He and Otto do restrain themselves from killing anyone. Enoch limits himself to praying quietly. Cortana admits that the translation from UNSC standard (I've always assumed it was English) to Gothic will take "days," the Space Marines accept and wish to be briefed on the Covenant xenos, taking all five Spartan-IIIs and four of the Spartan-IIs, who have remained silent and still the whole time, up to the battle barge to learn and brief the new "allies." During the week they learn as much about the Covenant, dubbing them xenos AND heretics due to their religious beliefs, and teach and spar with the Spartans, finding the "primatives" to be way faster and have a higher capacity for intelligence, however misguided, than they are. The Spartans do not, however react well to servitors. The Astartes are fairly impresssed with the Spartans, and that none of them died during practice [melee] combat with them. Reminding the players the human race is still on the technological upswing here, and a lot of their technology may well be superior to the Imperium's is at M41.
They meet with Halsey again, and Halsey has begin to go through the information, Cortana knows everything even parts "blacked out" in the file but has not spoken to anyone about it. She knows exactly what the Space Marines are meant for and how they operate. They begin to make ready to go fight the Covenant when they are alerted to the situation in Visigrad Relay to which the Astartes go to handle directly, with three Spartans with them as observers. Enoch fires his heavy bolter for the first time as they are fired on in high volume by grunts with plasma pistols, the destruction these weapons deal is impressive to all of the UNSC personnel present. Ar'nuld fires his plasma cutter (counted as a plasma pistol) and vaporized the highest ranking elite in the open, while firing on grunts with a bolt pistol. Otto opens fire with his bolter. Covenant forces rush the platform only to see one elite killed outright with a punch with a krak grenade left inside, and the rest of the grunts and jackals smashed between a devastator and techmarine. The remainder of the Covenant run and are cut down but the Astartes, finding plasma grenades explode easily. Moving into the relay they find the UNSC personnel attempting to fix the relay, Ar'nuld proving to be no extra help here.
They decide to scout out the rest of the facility, stealthily down the dark halls, Ar'nuld giving no help but staying behind. The Salamander is ambushed from behind by three higher ranking elits and pinned down, as the leader gets ready to introduce him to an energy sword, his servo arm gets ahold of its head and rips it off. He throws off the other two and they can't act before the other two Astartes come around the corner, Enoch grabbing one by the head and smashing it into a wall, breaking its shields, Otto slashing the other with a chainsword and breaking its shields. The pinned one attempts to get free but can't thus is double taps Enoch in the chest, wounding him (the wound is soaked) and the other runs off and cloaks. Enoch then gets his heavy bolter and unloads it into the elite. The other continues to evade, trying to escape. Otto stays on his trail until the Elite gets behind him and tries to kick out his leg (Otto has ajump pack on and is taller, it did this to get a better shot at his vitals arond the jump pack), it fails and Otto fires the jump pack, blowing its active camo away and getting some distance before returning to remove most of its limbs away with his narthecium blade. dragging it back by a broken arm to the rest of the humans. They wonder if they wish to interrogate it, the humans respond they have no way to communicate with it.
Otto shows the elite the Emperor's Mercy with a bolt pistol to the head. The humans are impressed if disturbed more than a little.