Because of the difference in the history and year between the two franchises, I'll make a quick rough timeline of the merged universe of this crossover:
1967 - Creation of NSC by the US government (Cyberpunk/Halo version of NASA) for the purpose of racing the Soviets to the Moon.
1969 - USA (more specifically astronauts of the NSC modified through Project Orion) lands on the moon first, NSC discovers forerunner technology in the form of a half-destroyed Keyship with single surviving Forerunner AI - Head of the NSC destroys all records of their extraterrestrial findings for fear of its misuse by the American Government.
1972 - NSC finishes excavation and retrieval of Forerunner technology - starts to reverse engineer the fleet for advanced spacecraft and software systems.
1974 - NSC finds further Forerunner artifacts and constructions in Kenya, Africa - further excavation occurs until Africa accuses USA of invasion. US Government questions NSC on their intent but NSC remains silent.
1978 - NSC succeeds in the first creation of a Dumb AI, utilising the blueprints they have managed to research from the Forerunner AI. They also start on building NSC Armstrong - the first space ship capable of long-duration space travel.
1984 - Degenerating society and slow collapse of Earth ecosystem leads to NSC planning Project Monolith: NSC officials and family members, and select few population is taken on NSC Armstrong to travel to outer solar systems, and colonise new planets - Primitive Slip space drive and terraform engine near completion.
1989 - NSC is forced to disband due to the formation of the Gang of Four (NSA, CIA, FBI, DEA) and their start of the "Quiet War" - NSC Dumb AI and Forerunner AI calculate and predict that Earth society will collapse due to the action of the Gang of Four by 1994. Former members of the NSC join to form a non-governmental organisation dubbed the United Nation Space Command (Due to recruiting various personnel from different countries - including ones that has hostile relationship with the US) - UNSC initiates Project Monolith, destroying any evidence that points to the existence of NSC and Forerunner technology. Previous Government officials that knew of NSC are recruited into UNSC or assassinated. UNSC leaves Earth without leaving a trace that they were existed, taking roughly quarter of Earth's population with them (Earth has named this 'the great disappearance'). UNSC still watches Earth even after leaving it.
1991 - Reach is Terraformed and Colonised, UNSC establishes itself as a de-facto militaristic government. Several other planets are starting to be colonised. ONI is derived from UNSC as the intelligence division.
1994 - Earth suffers from the Great Collapse, reducing several lands into deserts, humanity suffers from famine as several crops and animals die.
2020 - Due to UNSC-derived corporations and manufacturers mistreating colonies, Insurgent parties have started to form, UNSC now deals with Insurrectionists. First creation of Smart AIs, project spearheaded by Dr. Halsey.
2021 - SPARTAN-II Program is initiated, lead by Dr. Halsey. Flash cloning in development.
2027 - 150 candidates of Spartan -II programs identified through DNA gathered from UNSC's Outer Colony vaccination program.
2035 -
'This is Spartan Group Omega. They want war, we'll give them war.'
UNSC encounters the Covenant. The Human-Covenant War starts, and Cole Protocol is established. Among 150 candidates, only 33 survived the procedures without physiological deformities (1 commits suicide upon encountering their flash clone, 1 manages to escape to Earth and replace their flash clone back with themself)
2047 - SPARTAN-III Program is initiated, lead by Colonel James Ackerson.
2055 - SPARTAN-III Program Beta Company is initiated - Noble 6 is conscripted. Trained, and becomes a Spartan-III.
2068 -
'Negative, I have the gun. Good luck, sir.'
Fall of Reach. Noble Team is among several Spartan Casualties (UNSC officially classified their deaths as MIA) - Noble 6 manages to escort Cortana to the Pillar of Autumn, officially goes MIA (Managed to survive the Zealot-Class onslaught thanks to Heretic spies infiltrating the Covenant Ranks, quickly escorting Noble 6 to their ship before his location was glassed). Noble 6 strikes a deal with the Heretics: assisting their insurgency against the Covenant.
Thanks to Master Chief and Cortana's efforts, Halo ring is discovered by the UNSC and Sangheili has been split apart from the Covenant - Remaining Heretic forces joins with Thel 'Vadam and the UNSC, Noble 6 is reunited with surviving Spartans.
During the War, Covenant forces lands on New Mombasa - Earth's first contact with extraterrastrials, and find the existence of UNSC during the war. Many Conspiracy Theorists believe UNSC to be also be aliens - only wearing the appearance of Humans to hold better grounds with Earth.
The Human Covenant War ends.
Due to the success of Spartan IIs and IIIs, UNSC initiates Spartan IV program, with surviving Spartan IIs and IIIs receiving the chance to join the newly created Spartan Operations division.
2074 - Created Conflict occurs, lead by Cortana. Jiralhanae planet Doisac destroyed. Earth held hostage by a single Guardian. Earth has dubbed this 'Rise of the Machine god'. Few factions (including part of the Voodoo Boys) have decided to worship this Guardian.
2075 - Created Conflict ends with Master Chief detaining Cortana, however Banished forces ambush UNSC, causing UNSC to be shredded and forced into small pockets disconnected to each other. One of the Remaining UNSC forces - UNSC Revenant, travels to Earth to rebuild UNSC.
"Alright, I'll keep the briefing short. With only 6 hours before we arrive on Earth, UNSC Revenant is getting ready to start its front as a Megacorp. But to do that, we need roughly 3 things: Funding, Intel, and Connections. Spaces for our factories and buildings, and protection during their construction are mandatory too."
Agent Washington looked over the Spartan team he had gathered in the hanger bay.
All 5 Spartans IVs focused their attention on their Commander's order.
"So we're being sent down their for Recon."
"Close. We'll all be going down there at the same time. Your Fireteam is going down there as a form of Black Ops Unit. Objective is short and simple. Gather funding for us to use to properly establish a business within Night City's market, gather intel regarding the City's social structures as well as other Corporations, and finally gather connections we can use while we 'officially' open up for business."
"That feels a little difficult to accomplish while we remain as a Black Ops Unit, commander." The leader of the Spartan group quipped as he fiddled with his rifle.
"It won't be as hard as you think. According to our pre-established intels, business as a mercenary is booming in Night City. It's a perfect front to use during your operation. Of course, you guys won't be the only one sent down their with such objective. You'll simply be the first.
From here on out, all Spartan and ODST fireteams deployed for long-term on Night City will be grouped as Project: Freelancer. Do you have any questions?"
A Spartan IV that was sitting on a weapon crate raised his hand, the knife he was fiddling with during the briefing raking across the crate's surface.
"Are we being sent through an ODST drop pod, sir?"
"No. That won't be necessary. You'll be landing along with the rest of the workers on a designated location outside of Night City's centre. While Spartan Cell's group starts establishing a proper field for our operations, your Fireteam will head to Night City."
"Sweet, it's like Reach all over again."
"In addition, any weapons that could be traced back to us is prohibited. I doubt Night City and the MegaCorps within will take it kindly to finding out we started to poke and prod into their business the moment we landed on Earth. Only Spartans tasked with Security and Defence will be allowed UNSC equipments. Leave any guns and ammos here. You guys are Spartans, it shouldn't be too hard to acquire weapons once you manage to infiltrate Night City."
"Can we take our knives?"
"Can you guarantee me that you won't lose them?"
"No promises."
"Then the knives stay here as well. Like I said, we can't afford them to find out about your operation before we can manage to firmly establish ourselves. The only reason why I'm even letting you guys take your armour is because I know they'll barely recognise Spartans."
"Won't they know of our existence?"
"Technically yes, but realistically no. New Mombasa certainly still remembers us from 8 years ago when it got decimated by Covenant forces. Thing is, the only Spartan they did see is Master Chief. And according to the media, they all just think he's a really strong cyborg, or an android."
The leader once again raised his hand.
"Commander. I'd just like to confirm some details- the fail you sent to me says that their will be 6 of us. Will that mean you'll be joining us on this Black Ops?"
"No. But I'm glad you asked. You will have a 6th member joining you. I'll introduce you to him once I finish briefing you 5. Don't worry, he's not a rookie. So you don't have to expect to carry him around until he can start pulling his own weight. Any further questions?"
"How long will this take?" The final question from the Team through the Leader.
"At the shortest it will take 2 to 3 months."
"At the longest?"
"5 to 6 months. If you think you need any maintenance, I suggest you go to Engineers now. I'll be showing you the newest 6th member in the War games in 15 so meet me, and sending all 6 of you down their in 30. Make every minute count."
Agent Washington left the Hanger Bay, and shortly after the rest of the Spartans started to leave as well.
2 started to drop their weapons back in the armory, while the rest went to finalise their maintenance.
They all met together on the observation deck, the glass wall showing the War games field below.
They saw as Fireteam Eagle slowly sweep out the area, closely checking corners for the enemy.
"He's taking 5 of them on by himself…"
Noble 6 reveals himself again behind one of the pillars, grabbing another Spartan IV from behind and swiftly dragging them back into cover. Barely an audible gag was heard from the poor Spartan IV as they were forced to retire from the wargame.
Assassination. Swift, deadly, efficient and effective.
Bypasses the Mjolnir's shield, too.
"And he's winning."
"To be fair, did we expect less? It's Noble 6 we're watching. You know, Hyper-Lethal? One of the only two Spartans with such a classification?"
"The Covenant spent roughly a week just to focus on him. Sent several Zealot Classes to kill the Spartan."
"And they failed."
"That's why we call him the Ghost of Reach."
The Fireteam witnessed as the surviving opponents slow backed away from the pillars, each covering their comrade's back so that they cannot be caught off guard.
Noble 6 appeared from the corner, quickly incapacitating a Spartan with a DMR and dragging them into the shadows.
The Spartan could only scream, letting their teammates hear his voice bounce off the walls and echo into the void.
At least they tried.
"… Did anyone see him move from the pillar to the corner?"
"If I did, I would've pointed it out."
"Commander, are you sure that you want to deploy Noble 6 so quickly? I've heard that it's only been 48 hours since he return to active duty."
"He's the one that asked for it. Besides, 48 hours is more than enough for a spartan."
War games ended in 5 minutes: The score showed 50 to 0.
So much for cooperative team manoeuvres.
Noble 6 walked out of the fields and into the observation deck, as ordered by Commander Washington.
All the Spartans within the observation deck stood up straight as Noble 6 entered through the doorway.
"Commander."
"Noble 6, I've got some good news and some bad news. Considering that I want to end this conversation on a high note, I'll start with the bad news. Half the Spartans on this ship are idiots, and the other half are just one bad day away from becoming insurrectionists."
"And the good news?"
"All five of the Spartans you'll be assigned with are smart. Noble 6, I'd like to introduce you to your new Fireteam. This is Fireteam Baba Yaga. You guys will have to introduce yourself individually. The Chief Engineers are wanting to have a chat with me on our project. Get ready, you guys will be leaving the ship through a Pelican in 15 minutes."
All 6 of the Spartans followed their commander out of the deck, separating from Agent Washington once they've reached the Hangar Bay.
"It's an honour to work by your side, sir. I'm Locust, the leader of Fireteam Baba Yaga."
"Commander."
Fireteam Baba Yaga was starting to reach the Pelican, and each of the 5 started to put on their helmets.
Agent Locust wore a Rakshasa-class Mjolnir with a Locus helmet up-armored by PROJECT ENOCH.
For Black ops missions such as this, the ability to speak with tonal patterns that nearby humans can understand, yet unable to be interpreted through recordings or remote monitoring was perfect.
"The ones behind me are Leon, Killshot, Ram, and Jim."
Leon, Killshot, and Ram wore the standard Gen 3 Mjolnir, the differing in chest pieces, shoulder pads, and knee guards to specialise in their roles.
Leon wore a Celox helmet, the knife holsters on his shoulder guards, chest piece, and legs wore empty. Felix did not like that one bit.
Killshot wore a deadeye helmet with a RS[3]/WOLFTOOTH attachment. It meant that he'll be staying in the back line a lot, and would have to be quick with the information he gathers.
Ram wore a Courier helmet, the armours certainly made him look bulkier than the 3, pointy chest armour attachment blocky shoulder guards hid pockets and sockets for secure data storage with a datapad on his right wrist.
Jim looked like the outlier of the team, wearing a Mirage IIC armour instead. Fraction of the cost of Standard Gen 3 Mjolnir, and meeting the minimum baseline of the Spartan's suits.
But that didn't matter. Guy stood nearly at 2.4 metres, his shoulders were at the height where average Spartan IVs had their heads. His stature definitely made the armour look the bulkiest. ERINYES helmet and their attachments were installed and uparmoured on the Mirage IIC, hexagonal plates plastered all over the Spartan's body. The software made through Forerunner's War sphinx technology covered whatever shortcoming the Mirage IIC had.
Everyone on the team, including Noble 6, had their armour painted Steel-black, with only a few highlights in different colours.
Lime for Locust, Orange for Leon, Purple for Killshot, Red for Ram, and Silver for Jim.
Noble 6 was the only one that had Steel-black for highlights as well.
Each boarded the Pelican, nodding at the living myth or offering a hand shake.
"Jim's a Spartan-III like you, sir." Agent Locust added as Noble 6 shook the brute of a Spartan's hand.
"Nice to meet you, Jim."
"Honour." The voice that spoke out of the Mirage IIC was husky and monotone. Short, curt.
Noble 6 quietly waited for more, but Jim thought otherwise. Simply taking a seat in the Pelican and quietly waiting to take off.
"Big man doesn't talk much." Leon quipped. "It'll be a miracle if you hear him speak a full sentence. They say it's because of what he saw when the Covenants glassed his home. Some say it was a slight side effect of the Gamma Company's operation. You know, surgically getting their brain messed with."
Jim simply gave Leon a side glance before returning to stare at the floor. Leon snorted at Jim's passive defiance.
"Don't worry, he never bites. Not unless you order him to." That was the last thing Leon said to Noble 6 before he got a stern look from Agent Locust.
Noble 6 opted to move on from the conversation.
"Welcome to Baba Yaga. Agent Washington says we only need one bad day to become insurgents. I say we only need a minute of incentive."
"Agent Killshot, I doubt that kind of joke will be appreciated."
"But am I wrong, Commander?"
Whatever Agent Locust was going to say, the engine of the Pelican starting to blare drowned his voice out.
Guess it didn't matter. What was important was that they stuck to the objective.
Several Pelicans started to take off from the UNSC Revenant, a few holding newly created Assembler Vats that will be used to start the UNSC's Megacorporation activity.
Agent Locust already saw the file. Apparently Spartan Cell managed to complete the calculations that was eating him and Khyl from the inside - incorrect calculations of the nanomachines that would cause insufficient transformation of radiation from nuclear fission into additional matter. Detrimental effects of such miscalculations would be significant.
With only 7 hours on the clock, Spartan Cell managed to do what everyone on board would consider a breakthrough - performing further calculations using extra dimensions and inputing such into current computers allowed Forerunner software to be safely translated into current human software, allowing programming of the newly improved nanotechnology capable of reducing any scrap it has been fed into starter feedstock, and then create whatever the blueprint inputed through such transformed materials (and also siphon some of the nuclear energy to power the nanomachines)
Broken Assembly forges were repaired and quickly modified based on these newest calculations, and the reverse-engineered Assembler vats were termed 'The Cell-Khyl Vat'.
Agent Locust was glad to have Ram on their team. Ram's older brother was capable of utilising and integrating Forerunner technology, and Ram himself was just as capable as Cell.
Night City saw as a gigantic ship invaded the sky, with several smaller ships coming down to the surface of the badlands.
'Good Morning, Night City!', Everyone would tune to in the morning after.