Two Universe collide after the Forerunners fall and the Reapers return, will the two branches of Humanity placed in their respective Systems by a Forerunner Monitor unite or fall, only time will tell in this epic clash. When the UNSC Exploration and Research Vessel Light of Sol discover a strange artifact, they are opened up to the rest of the Galaxy after millennia of isolation.

The Gravemind was a thousand billion minds. When Halo wiped out the vast majority of it, a small core, a Keymind, was safely ensconced in its own private pocket of space. Yet They were not alone there. There was a reason that the Gravemind never referred to John-117 as Demon. He could never match up to the horror and power of the real thing... Metroid. Oneshot, spoilers.

During a Batarian Slave Raid on the Systems Alliance Colony of Eden Prime unknown defenders both Human and of unknown alien origin aid in the defense. While the UNSC and XCOM join forces under a thought long dead UNSC Rear Admiral and navigate this new universe, how will the future of Mass Effect change and will it change for the better or worse. - Mass Effect - Halo - XCOM Cross.

His memories are a mess, his life, reduced to fighting for the UNSC and ONI and his team's mission, doomed from the start. Noble Six's story had always been tragic to anyone who had half a heart while reading his file. To him, it felt normal, like it had happened before. He stalks the battlefields like a Reaper now. And his next mission, remembering, may be his toughest yet...

As the Autobots and Decepticon stumble across a strange device that is of unknown origin. As one of their human friends accidentally activates the device it transports the two wagering factions and humans into a different universe where they landed on a dead planet that belongs to an advanced humanity a few years prior to the war with the covenant been over.

Her extraction had failed. As the needles pierced her armor, she thought of her family; her brothers and sisters. It took a long time to see them as more than other conscripts, but she eventually found her way. Laying on the landing platform should have been her end, yet death had other ideas. Opening her eyes to another world, will Daisy - 023 survive this new onslaught?

Crippled by the Created and with their forces stretched thin. The UNSC must deal with a powerful and ruthless enemy who will stop at nothing to conquer everything in their wake. It is up to the crew of the Spirit of Fire to stop the Banished in a galaxy that is at war. Before the Banished unlock its secrets.

What Happens when a Forerunner Warden that was once a pony that was loved by the two Princesses Celestia and Luna has been in a state of stasis for over a thousand years was awoken by the Mane 6? Will he be able to reconnect with those he loves? (Dead)

Twilight tries to create another portal but this one backfires. Horribly. How will she get home? Will she Endure?

Arbiter awakes in a strange place, surrounded by both familiar and unfamiliar faces.

What if three Universes once separate come together. three different humanities with three different paths of technology merge into one galaxy. Citadel space will never be the same because the Schahl Empire and UNSC are here. Two Civilizations, one at war and one ready for war.

What do you do when you wake up in an old ship, in a galaxy far, far away? just survive.

They trained 10 years to become the new generation of heroes. Now as villains attcks USJ the SPARTANs reveal themselves to the world.

Commander Shepard and his team have gathered together the races of their Galaxy in an effort to defeat the Reapers. But is it enough? When the team comes across a strange woman they find out that if they are to truly defeat the Reapers once and for all. They will need all the help they can get. But not from their Universe. Multiverse Crossover! Chapters 6-22 Being Rewritten!

It was surprising, ending up here in this world, with a father and a mother that I wouldn't lose the Covenant, but I wasn't going to mess this up. Who I was doesn't matter anymore. What matters is who I am now. My name is Rudeus Greyrat, and I, am a spartan.

What happens when one of the most lethal soldiers the UNSC had trained finds himself in a world like he would never imagined, he will face his most difficult mission ever and maybe he will discover that he wants to stay[ CHAPTER 15 IN PROGRESS ]

Occurs after the events of Halo Infinite. Cortina finds out about a new enemy from the void of space called the reapers who are trying to rule the galaxy sending a warning to her former allies and enemies to unite the, she assigns chief espranza and the Weapon on a mission to unite the Citadel species to fight a war to end all wars in the Galaxy, can they do this task

When you die, and wind up meeting a precursor, and it offers you a deal, do not accept it. This is my story as a warning, as to avoid making a deal with these manipulative being's... This is my story how I wound up as a precursor because a female precursor decided to pick me as a candidate. (self-insert) (slight AU)

Two breeds of soldiers were bred for war and both with one singular purpose. Rated T for violence, death, and profanity.

The mission's changed, they always do. Sam wasn't expecting entering another world with no possible way back, but his missions objectives remain the same, "Protect humanity, no matter the cost." At the same time, he will be forced to come to terms with his new home and learn what it means to be a hero in this new world. At least he doesn't have to do it alone. Sam and Big 3, C-2A

With the help of the highly-motivated extra-species in the military, mankind holds their own against the brutal onslaught of the Covenant. In their haste to close the gap in space warfare, ONI stumbles upon Relay 314. Even as new enemies arise, the galaxy constantly thwarts Cortana's schemes to build the Master Chief the ultimate harem. Halo/Mass Effect/Monster Musume crossover.

A crashing ship brings a new empire and a new war with new allies for the Tau. Rated T for violence, death, and profanity

Here are some creative descriptions for a very unique crossover concept, combining Animorphs & Halo. Come for the art, stay for the writing. Maybe this will be expanded upon in the future?

Soon after the war with the Covenant, humanity discovers a Mass Relay that opens the door to the rest of the galaxy. But it also awakens the greatest threat humanity has ever faced. Male Shepard/Liara. OC/Krystal (from Star Fox).

After their escape off the Ark, the Chief and Cortana find themselves home, albeit, in a different universe altogether. Sensing a new purpose in the aftermath of the Human-Covenant War, the Chief is here to finish the fight.