This type of crossover category is something that is pretty large for sci-fi nerds like ourselves, and it has a lot of good stories, and several ideas. I've had a few ideas, and I'm hoping with ya'lls input whether or not to go through either one or the other so for now, I'll just put this up and let you guys decide. But both of these ideas will take place during Mass Effect 3, now some of the events within the game's universes have been deliberately changed in order to further the stories and ensure things flow smoothly.

Prologue – The Spartan and the Shepard

The night was bright with the stars shining down, as a grandfather and his grandson walked outside through the beautiful snow filled forest back home.

"Did all of that really happen?"

"Yes, but some of the details were lost as time went by, but yes, she did do all of those things."

"And what about the Spartan and his friend?"

"They did stop the menace from spreading across the galaxy, but they were lost in space for many years before they were rescued."

"Was it the Shepard?"

"It was…" The grandfather looked up to see the stars in alignment telling him the time already, "…it's getting late, we should head back home."

"Aww, can't you tell me more about the heroes?"

"Well, I suppose so. It all started when the Spartan and the Warrior escaped the second ring…"

-December 11th, UNSC year 2552; Installation 04B, Alpha Halo's Replacement Ring-

"Gun it, Chief! Jump! Floor it! Right into the hangar

The Master Chief and the Arbiter had been driving back towards the UNSC frigate Forward Unto Dawn, avoiding an onslaught of Flood and Sentinels that had been trying to kill them in their escape of the now active Installation 04B over the Ark. 343 Guilty Spark had stated that a premature firing of the Installation would result in not only destroying the Halo, but quite possibly also destroying the Ark as well.

The Warthog makes the massive gap between the platforms into the Dawn's hangar bay but it doesn't land well, tumbling and rolling as it crashes into the frigate's hangar. The Master Chief and the Arbiter recover, then the Dawn shifts. A Scorpion tank begins to slide towards the Arbiter, who takes cover behind a pile of crates, with the tank plowing into it. The Chief leaps over the Warthog and hesitates, seeing the Arbiter digging himself out of the crates. The Chief nods at him, and the Arbiter nods back, both in knowing what to do. The Arbiter rushes to the bridge, while the Chief runs to a control terminal and plugs Cortana in to take control of the frigate.

Cortana then appeared with her glowing, light blue, holographic form on the panel.

"Hang on!" the A.I. shouted.

Cortana ignited the thrusters at full burn and launched the Dawn at full speed away from the exploding Halo. The Chief grabbed onto the terminal, hanging on for life as the Dawn left Halo's atmosphere. As the Spartan tried to stay anchored, the Warthog flew out, which struck John on its way through the open hanger doors and out into empty space. The Chief flew off the panel, and then glided down the floor towards the doors, with the self-destructing Halo looming beneath. The Chief punched his fist hard into the floor to get a grip, halting near the back end of the hangar. Cortana reached out her arm towards him, afraid to lose him. Her closest friend.

"Chief!" Cortana yelled with worry in her voice.

The Scorpion flew out towards the Spartan. Seeing the tank looming towards him, Chief ducked his head just in time as the tank flew over him, narrowly missing the Chief. The Scorpion smashed the floor behind the Chief and fell back towards Halo. John began to climb back up to Cortana. After a few seconds passed, the Master Chief finally made it to the holotank that contained the A.I he went through the Flood infected High Charity.

Meanwhile, the Arbiter made it to the bridge and sat down at the controls.

The Chief braced himself behind the panel as he reached his hand to the panel to recover Cortana's chip to plug her back into his helmet. The Spartan felt the cold sensation go through his body as his A.I. companion was once again in his helmet.

"If we don't make it..." Cortana said sounding as if she was accepting death.

"We'll make it." The luckiest Spartan replied in confidence.

"It's been an honor serving with you, John."

The Master Chief finally rested his head back, exhausted from the events that occurred on Earth, the Ark, High Charity, and Installation 04B. The Halo Installation suddenly exploded, which engulfed the hangar in a binding white light. Soon, the only thing they saw was a blinding bright light before they blacked out.

-March 3, 2553; Earth, outside the portal to the Ark in the ruined industrial city of Voi-

There stood, on what is now UNSC's most important and respected memorial, Lord Hood, the Arbiter and seven Marines armed with Battle Rifles.

Lord Hood now started one of mankind's greatest speeches. He took off his white military hat to pay respect for those who fallen and have made a huge contribute to the war.

"For us the stormed has passed. The war is over.'' Lord Hood bowed his head to show his endearment, "But let us never forget those who journeyed into the howling dark and did not return. For their decision required courage beyond measure…sacrifice, and unshakable conviction that their fight, our fight, was elsewhere."

The Arbiter watched the memorial, the Elite stood solemnly with the Marines. He listened to the UNSC's leader say his speech for the human's heroes that died in action to the onslaught of the Covenant and the horror of the Flood, so humanity can live on.

"As we start to rebuild, this hillside will remain barren, a memorial to heroes fallen. They ennobled all of us, and they shall not be forgotten."

Admiral Hood placed his hat back on, and saluted.

Sgt. Stacker issued orders to the marines, "Present arms!"

Seven Marines raised their Battle Rifles with the pride and each fire a single burst of three shots: a 3-volley salute.

Later, Hood and the Arbiter stood alone at the Memorial, which appeared to be a Pelican wing, decorated with pictures of the fallen, including Captain Keyes, Sgt. Johnson and so many other soldiers that fought bravely for humanity.

"I remember how this war started. What your kind did to mine. I can't forgive you. But..."

Hood held out his hand to the Thel Vadam, the Arbiter.

"You have my thanks. For standing by him to the end." Lord said as he made a reference to the one who won them the war.

The Arbiter slowly shook Admiral Hood's hand with his own four fingered hand. After letting go, Hood turned to the memorial once more to look at a sad site that he thought he would never think they would ever see or really anyone would ever see, the Arbiter shared Lord Hood's sad gaze.

"Hard to believe he's dead." The UNSC leader said with sadness, still not wanting to believe the most famous Spartan, that won the war for the human race, is with other Spartans that are M.I.A.

The Elite in black ancestral armor looked away towards the Assault Carrier, Shadow of Intent, which hovered silently in the sky of Earth.

"Were it so easy." The Arbiter finally spoke to Lord Hood. A phrase he said to Master Chief when he saw him on Earth, when the Spartan aimed a Magnum at his throat.

Thel Vadam left the Memorial. His Separatist Phantom headed back to the Shadow of Intent, which still hovered in about the same position the Portal to the Ark once was. The Arbiter meet Shipmaster Rtas 'Vadum on the bridge. The white armored Elite with some missing mandibles looked at a holographic image of a planet. He saw the Arbiter approach him, and turned off the hologram of Earth.

"Things look different, without the Prophets' lies clouding my vision. I would like to see our own world… to know that it is safe." Rtas 'Vadum said as if he is looking at his home world for the first time.

"Fear not. For we have made it so." The Arbiter spoke with pride and confidence.

The Arbiter clenched his fist to his chest, as a sign of honor.

"By your word, Arbiter." Supreme Commander, Rtas 'Vadum spoke with respect as he repeated the gesture the Thel Vadam made.

The Arbiter took a seat on the command chair, as he assumed command of the Shadow of Intent. The silver armored Elite spun on his chair.

"Take us home." Thel 'Vadam commanded as he and every other Elite on the Assault Carrier, was eager to see their home planet, Sanghelios safe and sound.

The Shadow of Intent left Earth, to rejoin the remains of the Covenant Separatist fleet in space.

-Elsewhere in the Galaxy-

A feminine voice is speaking to a floating man in dark green armor.

"Chief? Chief? Can you hear me?"

The Master Chief, alive and awake, floated in zero gravity in a dark debris-filled hallway on board the Dawn.

"I thought I'd lost you, too." Cortana breathed a sigh of relief.

Chief turned on his helmet's lights and looked at a hole that was behind him in the hallway. He drifted to his floating Assault Rifle, and holstered it on the magnetic plates on his back. The Chief then began to drift towards hole at the end of the hallway.

"What happened?" The Spartan asked Cortana.

For once Cortana said three words that many people that wouldn't believe she would say.

"I'm not sure. When Halo fired, it shook itself to pieces. Did a number on the Ark. The Portal couldn't sustain itself. We made it through just as it collapsed."

The Chief reached the end of the hallway, which opened up into the vast empty space. The Forward Unto Dawn looked as if it was cut half perfectly, it floated in a cloud of debris, with ends of it still literally red hot from the Slipspace cut.

"Well...some of us made it." Cortana then spoke with a little disappointment as she referred to the Arbiter who was nowhere to be found.

The Dawn's remaining half continued to drift aimlessly in unknown space. The Chief decided to glide further inside the ship, finding a row of cryotubes, complete with a holotank to plug Cortana into.

"But you did it. Truth and the Covenant, the Flood..." The Chief plugged Cortana's data chip into the holotank and she appeared on the holotank with her glowing blue form. "It's finished."

The Master Chief turned off the flashlight on his helmet. The Chief placed his Assault Rifle in one of the rackets on the wall, so he could grab it incase anything happens.

"I'll drop a beacon. But it'll be a while before anyone finds us." Cortana said sadly.

The man climbed into the cryotube that was in-front of Cortana's holotank and next to the rack where he placed his Assault Rifle.

"Years, even." Which disheartened John since Cortana can only be active for seven years before she thought herself to death. The Master Chief began to think what he would do without Cortana in his life, but his thoughts were quickly interrupted, as the cryotube door began to close.

"I'll miss you." The A.I.'s words were filled with emotion that you would never thought a computer would ever have; sadness and care.

"Wake me when you need me." Master Chief spoke his final words to his last living friend on the half of the Dawn.

Cortana smiled and nodded her holographic head to John. The cryotube closed and sealed itself, which froze the Master Chief. Finally, the rest that Master Chief needed since he first encountered the Halos.

Cortana dropped the Dawn's beacon, hoping the message will get found so she and Master Chief could one day be saved. Little did they know that a Forerunner AI, was seeking repentance after its destruction, had sent them into the deepest parts of space, towards an ancient being, of unimaginable power.

But that would wait, for a less dark and ancient evil began to descend into existence once more…

-2186 Citadel Calendar; SSV Normandy SR2-

Just how long had it been since the Reapers began laying siege to Earth? Two days? Three? And how many dead? Millions? Tens of millions? Who could really tell or keep count of the casualties right now?

Commander Jane Shepard had been getting ready to head to the Citadel after picking up the Turain Primarch from Menae, with Garrus joining up once again, and discovering the last Prothean alive, but lady fate seemed to say neigh to her plans.

"Commander, you have an incoming message from Admiral Hackett in the QEC room."

EDI spoke over the intercom in her cabin up top of the Normandy, it was something she had grown accustomed to, during her time when she was commanding her little 'Suicide Squad' back when the Collectors were taking colony after colony.

"Did he say what for?" Jane had made her way to the elevator down the next level. The Alliance had done heavy and extensive retrofits when she forked it over to her superiors, and then she was arrested for supposed crimes against the Citadel and Alliance, sans the Alpha Relay that she destroyed that bought them six months' extra time to prepare for the Reapers.

Lot a good that did…

She exited the elevator and had gone through the security checkpoint and was walking through the conference room.

"No. He said that it was an urgent matter however."

"Alright, I won't keep him waiting then."

She walked into the QEC room and the image of Admiral Hackett came through, "Commander Shepard."

The young commander saluted to her superior officer, "Admiral Hackett, sir. What was so urgent that you needed me to break off from heading to the War Summit?"

"Our intelligence came across a distress signal, coming from somewhere deep in the Terminus Systems..."

Hackett looked pretty anxious, though who really didn't look and feel that way, but this seemed more so than usual, "…possibly in the far rim near the edge of the galaxy. It was bouncing between a few of our comm buoys before we managed to capture and isolate its contents, but I have feeling that we weren't the only ones that heard it, despite it being encrypted."

Referring to the Reapers, to Cerberus, or anyone else that would've taken an interest in the message, "What's the message say?"

Hackett punched up something on a console off view and the audio played through the speakers "Mayday, mayday, mayday. This is UNSC FFG-001 Forward Unto Dawn, requesting immediate evac. Survivors aboard. Prioritization code: Victor Zero Five dash Three dash Sierra One One Seven."

Jane was already intrigued and in deep thought. From the way it sounded, it was military going off of the code given, and being encrypted sounded a little fishy though, "How long has it been broadcasting?"

"From what we can tell, about four years or so."

Her eyes were wide in shock, "Four years? How did we not come across it before? It's been broadcasting since the Blitz happened, at the least."

"It's possible the encryption kept it from being so widely transmitted, it could be a power failure from the point of origin, it could be that it was in a nebula and kept the transmission from being sent out…there could've been a number of things that kept it quiet until now, but I need you to investigate it, and quickly, before Ceberus or even the Reapers head to its location." He took in a deep breath, for his next set of news, "Not only that, but we ran the name of the ship through our databases, and nothing came up."

Now this set of news had her full attention. A ship that had no previous record, with a military encrypted distress signal, somewhere deep in the Terminus Systems practically on the edge of the galaxy, that's been awaiting rescue for four years.

This was her concern now.

"I'll head there and pick up the survivors immediately, sir."

"I'll leave you to it, Hackett out."

Jane walked out of the QEC room, and over towards the newly retrofitted War Room where numerous members of the crew were hard at work doing their jobs, she pulled up the galaxy map and wanted to know where exactly the transmission was coming from. For about six months or so, she had traversed the Terminus Systems while taking down the Collectors with Cerberus, and never once did she come across this distress signal at all, so which begged the question…

…why were they hearing it now?

"EDI, can you get me the distress signal's exact location?"

"I can isolate the cluster; however, we will need to get closer to the signal in order for me to narrow it down further. One moment please…" The map of the galaxy sprung up on the holotable as it began tracking the signal through the FTL comm buoys, to which so far it was heading near the Perseus Veil, past the Far Rim and towards where the very edge of the galaxy ended. "…this is where the distress signal originated. Once we draw closer, I can home in on the exact location of the ship."

Jane nodded, "Alright, Joker?"

"Already setting a course, Commander. It'll be a couple of days though, so better kick back and relax."

"Right, I doubt it's going to go so smoothly." Like the last few times they went to a derelict ship in the past.

Jane headed back up to her cabin to get some shut eye, to which she really needed right now. As she silently fell asleep, she began dreaming again…the same one as before.

She found herself in a dark forest, with a little girl running away from her. She tried to call out to the child, but her voice was gone, her legs moved, but it felt as if she barely had any strength left in her. As she continued chasing the child, she found her surroundings changing, the forest was slowly becoming infested with pieces of, what looked like rotting biomass covering the ground and the trees.

The air was becoming polluted with spores, and green mist, but the forest began to disappear and large floating metallic spires began to rise from the ground, and purging the rotting biomass from the ground. The sky began to glow an eerie orange, and the mist started to clear, but she started choking with a violent cough.

The child stopped at the edge of a platform that overlooked a massive valley that was in flames. Jane ran up to the child with an outstretched hand, holding onto hope that she could reach her in time, but as she neared closer and closer, she heard the girl's voice…but something was wrong with it.

"Jane…if you join me, you'll be at peace."

She turned to Shepard only to reveal herself to the shocked and horrified look on her face.

"You'll be at peace too."

Her flesh was rotting in a disgusting brown, with her head now pushed off to the side. A trio of tentacle like claws now protruded from her left arm and shoulder, and pus and spores began to pour out of her twisted mouth.

"You'll be at peace too."

The girl, now wore a sickening smile, as her eye sockets were black with no life. As the sky began to glow brighter, a symbol started to take shape within the mist; a fully colored hexagon within a circle, connected by two line on both sides, and a bar resting atop the hexagon.

"You'll be at peace too."

Her voice now began to change into something otherworldly and demonic. Not filed with the arrogance of the Reapers, but with an air of insidiousness.

"You'll be at peace too!"

The girl's body then leapt out at her with the intent to kill her, but everything disappeared in a flash of orange when the symbol grew to consume everything…

Jane woke up in cold sweat, with fear in her eyes. Fear for her life; something she hadn't felt in so many years. She walked over to the bathroom and splashed some water on her face and saw that her hands were shaking, she hardly ever did that.

The girl that she saw on Earth had been killed by a Reaper Destroyer as the shuttle ferrying civilians was downed within seconds. She was haunted by that moment as she was helpless to say or do anything. She had a dream shortly after talking with the council on the Crucible and trying to get them onboard with uniting to take Earth back, of the same girl, running away from here, hearing the sounds of Reapers chasing them down, and finally the girl bursting into flames just as she was about to reach her.

But now…whatever she felt then, was pure fear of the girl…

"Commander, we are nearing the signal's source."

"Thanks, EDI. Tell everyone to gear up, no telling what we'll find." And with her recent dream, well there was no telling what they'd fight…hopefully they wouldn't have to at all.

-The wreckage of the Forward Unto Dawn-

The Dawn had been floating aimlessly throughout space for three years, so far nothing interesting had happened, but now something shook the ship. Inside the cryo chamber, a sphere of blue light hovers above a holographic projector. The sphere disappears in a flash of blue, replaced by the figure of, Cortana, who appeared sitting on the holographic projector, letting out a small gasp as she did. When the severed Frigate had started rumbling, she knew something was wrong. She was distressed enough already, but when the ship shook she began to worry.

She slowly stood up, and after gazing around the room for a few seconds, she brought a holo-terminal. She quickly browsed through a status report as the ship continued to shake:

SHIP STATUS: CATASTROPHIC LOSS, ALL DECKS

SYSTEM STATUS: 6% SHIP SYSTEMS ONLINE

LAST CONTACT WITH UNSC: 4 YEARS, 1 MONTH, 7 DAYS

LOCATION: UNKNOWN

CREW CAPACITY: 782

CREW SURVIVING: 1

Cortana didn't see anything that could help her, so she brought a schematic of the Dawn. Several red rings appeared in multiple places throughout the ship, indicating several integrity failures. Cortana knew that, in this situation, it meant only one thing: they were being boarded. She ruled out the UNSC as a possibility, since they would have first tried to initiate contact. That left only one other known possibility, and she did not like it one bit.

She immediately brought up the cryo chamber's control interface, all the while becoming increasingly agitated. A schematic Cryo-Tube 16's single occupant appeared, alongside life signs and cryo-tube diagrams, as well as a single prompt:

REACTIVATE

Cortana hesitated for a moment, unsure if she should wake the occupant up or not. Seeing no other way, she accessed the prompt.

FOD=9939 DECK 4 / CRYO SUBDECK. ARRAY=93

CRYOGENIC SYSTEM SHUTDOWN . . .

STASIS CONVERSION IN PROCESS . . .

ACTIVE

Cortana sighed as she turned to observe Cryo-Tube 16. As air pumped into the tube and the ice covering the glass surface melted away, she remembered the advice given to her by the occupant all those years ago. It was time to follow it through.

"Wake up, Chief. I need you."

I'll stop it here for now, with the next chapter taking place aboard the Dawn and whatnot. Now, the story of Mass Effect 3 will continue on, along with Leviathan, Omega and Citadel DLC's. Some of the things that I've altered, mostly Halo's history will be shown and explained, such as the fates of Grey Team, NOBLE Team, Black Team, Dr. Halsey, Miranda Keyes, etc.

The Covenant remnants will also make an appearance, though they will be different than in canon, as well as the Didact and his Prometheans. But they all won't make an appearance until much later in the story. Currently I don't have any plans to include the Guardians, the Banished and The Spirit of Fire so don't expect an appearance from them.

So be sure to read, review, favorite and follow my stories. Also, be sure to drop by my YouTube channel: The League of Gaming Nerds, leave likes, comments and subscribe.

See you guys next time :)