2 days ago, the day I was born... Disaster struck within the northern regions of the Northern Confederate States of Almarant and Quessientina... I would only know the full extent of the diaaster that the Demon Lord has unleashed a week after my reincarnation. 

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It's currently a really cold day within the Parliamentary Building of the Northern Confederate States of Almarant and Quessientina due to their country bordering the Northern Pole. Within the building lies the Office of the Prime Minister of the Confederation...

The Prime Minister is currently writing and signing some paperwork as a part of the newly-passed legislative that would've helped the naval rearmament of the Confederation in their fight against their enemy, the Dynasty of Musashi, when an explosion so reverberating and powerful-sounding were heard far from the northern sector...

A few moments after that, all of the guards who were guarding the outside the room immediately went inside the Prime Minister's office...

"Your Excellency!"

"W-What was that?!" The Prime Minister exclaimed as he also felt this surge of energy. 

"A massive explosion, Sir! From further north!" One of the guards said, being a magic swordsman that can feel mana far more intricately than a mage. 

As confusion was still prevalent in the office room's mood, multiple robed individuals came to the Office of the Prime Minister.

" Your Excellency, we have arrived for your protection..." A robed person arrived at the office. 

"Ah, Oskar! What's the status? And what the heck was that sound of an explosion?!" The Prime Minister exclaimed. Oskar's one of the Court Magicians within the Confederate States.

"Your Excellency, it's a Strategic-class mana explosion. It came from the North Pole."

"A Strategic class? There's no way that those ninjas could have the capabilities to create a Straregic-class spells. But to explode on this much of a scale... Is it the Gaia Federation?" The Prime Minister pondered. 

The Prime Minister quickly tinkers about what they should do. But before they all could arrive at a conclusion, loud running footsteps have been heard as it's approaching the office.

"Your Excellency!  Northern Command reports a huge swarm of flying monsters going southward from the north!" A soldier reported while heavily panting. 

"N-No way! Everyone, defend all of our citizens as much as possible! Knights! Bring out your anti-air ballista and fire upon those monsters! Mages! Support the knights by firing magic to the incoming monsters! The government will have to send our fastest messengers to the neighboring states at the south. Deliver the message that a monster stampede is coming. Let's get to work!" The Prime Minister immediately ordered everyone. 

"""Yes, Your Excellency!"""

As all of them who were inside the room left, the Prime Minister goes to a large cabinet and pulls up a magic staff, and muttered to himself.

"A huge mana explosion to the north... followed by a huge swarm of flying monsters from the same direction... What the hell is happening...?" 

After that, the Prime Minister then immediately left his office room and started going outside while taking down any flying monsters that he sees using his magic. But that's not just the only things that would come their way...

"Y-Your Excellency! We have detected a very large horde of monsters that are exiting the pine forests from the north!!!" One of the soldiers ran up to the Prime Minister as they were outside the parliament house.

"How large, soldier?" The Prime Minister immediately asked.

"I-I don't know, Your Excellency. The border guards have reported a huge number of monsters exiting the forests... Possibly estimated to be around tens to hundreds of thousands..." 

The soldier delivered an information like a bomb dropped on the Prime Minister's mind. 

"Monsters?! N-No way... I-It's the stuff f-from the myths..." Indeed, there was... There's a story that has spread through everyone as a mythical fable.

A subject of mythical fables of the past, they knew it that the events  that have unfolded were the same as the story suggested. Accompanied by the incoming black fog, there's only one possibility that connects to all of these. 

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5,000 years ago, the world as they knew was once a land where battles between races have been an everyday occurrence. Humans, elves, beastmen, and mer-people were at odds with each other.

Constant fighting and chaos between these races, their inner factions, and those with ulterior motives have created what's known as the "demons" from the grudge, despair, grief, and especially, hate that all sentient beings felt that propagated the world of Tierra into its darkness.

All of this darkness along with the advent of spirit, magic, and holy power towards the four races that came from all of their infighting has resulted to the creation of the "Demon Lord". 

The Demon Lord is the most powerful being in the world as of the time of its birth.

A menace that harbors all of the negative emotions that every sentient being has made toward one another, a menace that would kill any race that's blocking its path in order to assert dominance all over the four races.

Facing overwhelming odds, the four races have banded together with hope in order to stop the threat that the demons possess and formed a unified front. Each race then sent their most powerful elites which would later become the Hero's Party which is led by each race's strongest people. 

Along with the newfound affection that the Goddess of Creation "Anastasia" has discovered upon the unification of hope from all of the four races, the Goddess Anastasia has decided to gift them by summoning an individual from another world.

Known as the "Hero Sirius" by the historians that recorded its occurrence, the Goddess Anastasia has made him so that he would have the ingenuity and wisdom of a human, the strength and resilience of a beastman, the longevity and intricacy of the magic of an elf, and the courage and dexterity on weapons of a mermaid all within the body of man.

The factors that have made the Hero Sirius who he is has inspired all of the unified forces in order to defeat the Demon Lord which all culminated in what is described as the Tierran's unified counterattack against the Demon Lord. 

Along with the unified alliance, the Hero's Party, consisting of the Hero Sirius, the Head Pontifex Rossiya, the Great Magus Elftraut, the Warrior King Valerio, and the Mermaid Queen Mariela ventured deep within the Demon Lord's territory in order to defeat the Demon Lord head-on.

And defeat them, they did... After numerous trials and tribulations, the Hero's Party has defeated the Demon Lord with the Hero Sirius himself swinging the final slash from his holy sword Avalon.

The Demon Lord was no more, and with that, the era of both infighting and chaos has been over along with the defeat of the Demon Lord.

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"Soldier! Send this information to all of our messengers!" The Prime Minister said as he then added. 

"Heed my words and listen! As the last mandate of the Northern Confederation, evacuate all civilians to the neighboring countries of the Holy Empire and the Elven Confederation! Tell the world that the Demon Lord has been reborn! The rest of us will keep delaying the Demon Army's advance!" The Prime Minister declared. 

"Y-Yes, Y-Your Excellency!" 

The knight who was with the Prime Minister replied as he immediately ran towards his superiors. Multiple smoke signals have been lit up and numerous emergency bells are ringing, signaling the evacuation of the civilians within the capital of the Confederation.

A day after that warning was sent to the messengers, the entire territory of the Northern Confederation of Almarant and Quessientina fell to the Demon Lord's monster flood...

The day is the 17th day of First Earth Month in the year 5000 AP... The world would know that the Demon Lord has been reborn... 

And with it, a new hero will emerge to fight this darkness to reunite everyone as this person would restore peace and order to the world of Tierra.