In the year 1999, it was revealed to the people of planet Earth that there was a second world intertwined deeply with their own, formed of their own information network.

Eight Chosen Children, some called them Digidestined, saved this Digital World from a force of terrible evil, then all passages to that world were sealed.

Three years later, it became apparent that the Digital World was open again, when a new group of Chosen defeated one of their own, and at the end of that year, it's presence was confirmed when the Digital World's inhabitants, called Digimon, appeared in the Human World alongside several black towers called Control Spires.

After the defeat of the Digimon behind the plot, the two worlds became more closely intertwined, as people found themselves becoming partners with a Digimon.

By 2013 every human had their own Digimon partner, and many of the planet's inhabitants had moved permanently into the Digital World.

135 years later, explorers on Mars discovered the remains of an ancient spacefaring civilization.
In the decades that followed, these mysterious artifacts revealed startling new technologies, enabling travel to the furthest stars.
The basis for this incredible technology was a force that controlled the very fabric of space and time.
They called it the greatest discovery in human-Digimon history.
The civilizations of the galaxy call it...

MASS EFFECT

Hello, and welcome to the crossover fanfiction Digital Mass Effect. While the story of the game ultimately flows the same, the Digimon partner every human has has changed most human's perspective on the aliens of the galaxy.

The reverse is also true, as the Council believed that Digimon are a type of AI given strangely constructed platforms. It wasn't until the salarians sent a doctor and a scientist to study these so-called "digital lifeforms" that they were accepted as they were in the original story (though there are still many holdouts).

For the main story of Mass Effect, all of the human characters will have Digimon partners. Most people's partners never get beyond the Champion level, though many in the military reach Perfection level (I'll be combining Japanese and English terminology depending on what sounds better). The principal humans and their partners are:

Captain Anderson: Armadimon-Ankylomon-Shakkoumon

Ambassador Udina: Keramon-Chrysalimon

Admiral Hackett: Tentomon-Yanmamon-MegaKabuterimon

Kaiden Alenko: Kokuwamon-Thunderballmon-(Discovered if surviving Virmire)

Richard L. Jenkins: Leormon-Leomon.

Ashley Williams: Kotemon-Starmon-(Discovered if surviving Virmire)

Commander Shepard, however, will be determined by you. There is a poll on my profile determining Shepard's background. The Rookie level of his/her partner will be determined by a combination of the pre-service history and class, while the Champion level will be determined by the psychological profile.

For instance, my first Shepard was an Earthborn Sole Survivor Soldier. His partner would have been a Guilmon that evolved into Allomon during the disaster on Akuze.

The chosen background will also determine the choices during minor conversations, like Shepard's reaction to Wrex shooting Fist, while major decisions, like what to do with the Rachni Queen, will be decided by poll. These plot-line decisions will also decide the Perfection and Mega levels of Shepard's partner.

Continuing the above example, my Shepard's partner would have evolved into Aero V-dramon while saving Liara (having gone to Feros, then Therum), then into Gallantmon during the climax on Virmire.

To explain, the neutral choices result in Data evolutions, the Paragon choices result in Vaccine evolutions, and the Renegade choices result in Virus evolutions.

If this story does well enough, we might even see a sequel!