Long time ago, there were 5 kingdoms in Remnant. 4 of them went to war due to their greed and their thirst for power. One of them, the oldest. Saw the bloodshed develop and decided to intervene in order to put an end to the fighting.
They favored the cause of the West and handed their ancient relics to a mysterious king. Once the time came to claim them back however, the kingdoms turned their backs on them and kept the relics.
As seasons passed, the rest of the kingdoms began to erase any trace of this kingdom. Any contact, any family bonds, any sort of supply. Everything was kept away from this "uninhabited" landmass
The abandoned kingdom slowly succumbed to desperation. Starved to death. Stranded in a harsh land and cut off from the rest of the world, the people slowly began to revolt. With time, the kingdom broke into 4 dominions.
The Viceroyalty of Juno, by the north-eastern coast. The dominion of Volvangar, by the north-western coast. The chiefdom of Suidwes, by the south-western coast and lastly, the land of Dongnan, by the South-eastern shores.
"Or at least that is what the official history reads" says one of the students in Niflheim, defying the professor
"Well, it looks like Sinner has a doubt regarding the history of our nation" replies the professor
"Well, lets see. You say "Chiefdom" of Suidwes but Suidwes actually always had governors. You say land of "Dongnan" but it was rather ran by warlords that organized a council, which would make it a federation"
"Ah...Well, those are but minor details. Especially since now all of these are states, Pupil"
Sinner returned to their seat until he picked up a radio signal
"Orantes to Sinner. How copy?"
"Solid copy, Orantes. What do you have?"
"3 Grimm. Beowulfs. Can you see them?"
"Yeah. By the cliffside"
The professor takes some notes
"Shoot one and I get the other. Manzula will take the last one"
"I think maybe we shouldn't let Manzula take that last one"
"Just shoot one. I have the one on the left"
"I take the one of the right, since the treeline covers the other two"
"Alright. Over and out"
Sinner picks their carbine and aims down, right at the Beowulf
After some shots and a small brawl in the forest, the teacher blows a whistle
"Alright. Sinner, congratulations. You graduated. Come on, we're burying your teammates"
Sinner simply gets up and follows the professor. They walk down from the hill and into the treeline. They find the dead Grimm along with the corpses of Orantes and Manzula
The professor hands Sinner 2 Fire Dust crystals
"As any good reaper, you have to send them with your fallen brethren. Burn the bodies"
Sinner, with no doubt, breaks and throws the crystal's at both bodies after taking the weapons off them
"Good. Decision. Something useful"
The professor then hands Sinner a ceramic mask. It is black but very ornamented
"As of this moment, you are now Reaper Oculus, as your team was called"
"Thank you, Professor"
"Not Professor anymore. You and I are now the same. Reapers"
"Alright. Reaper Manticore"
"Good. Now, you're free to leave. Command will assign you tasks directly now. Until we meet each other again"
Oculus put on their mask and shouldered their rifle, then started walking on their way out of Niflheim, when they got a message on their pad
"Reaper Oculus. Join fellow Reapers at Trolesund. A manhunt has been initiated"