Prologue: 5 year war

"Come one, we're almost there so just hold on, ok?"

A young man wearing a tattered armor which was covered in blood said. Pulling his injured friend towards the fort of the city.

"You fuckin idiot, we'll both die here"

His friend cursed with a frown on his face, trying to convince him to just leave him behind.

"W-We're almost there so please just-"

He comforted but froze as he saw thousands of Gastreas come out of the dimensional rift.

"Fuck"

He cursed as he hurriedly placed his immobile friend on his back. Beginning to run as fast as he could to the fort.

"JUST HOLD ON!!!"

He shouted as he ran as fast as he could towards the fort that was a few kilometers away from their position.

"You idiot..."

His friend said with a light frown on his face before turning his head to look back at the large army behind them.

"But... thank you for being a great friend"

He said with a light grin on his face before he suddenly grabbed his arm. Forcefully letting him go of his immobile body.

"[Iron Wall]!!"

He casted as a small wall appeared in between them. Splitting them as he casted [Explosion] on the wall, propelling both the wall and his friend forward.

"W-Wait-"

His friend tried to shout but was too late as he was launched forward, leaving his immobile body behind.

"I didn't even got to say goodbye to my fiancée yet..."

He muttered before placing his hand on his chest.

"For the faction"

He muttered as he activated the [Core] inserted in all of their bodies so that they could kill themselves if ever they get captured by the enemy.

[Self-destruction has been initiated]

[Countdown has started]

The mechanical voice of a woman said as his chest started to illuminate. The man grinned as hundreds of mana circuits appeared on his body. Initiating the process of overloading his body with mana to create a bomb of condensed mana.

"Come and get me you shits!"

He shouted towards the thousands of Gastreas that were closing in to his location.

"HAHAHAHAHAHAHA!!!!"

He maniacally laughed as he watched a Tier IV Gastrea jumped at his body at full speed. 

As he saw the Gastrea inching closer, he smiled. Preparing himself for his own death. But to his surprise, before the Gastrea could land on him, it's entire body exploded into pieces.

"W-What-"

He muttered before he felt a drone attach to his back. Sucking up all of the mana on his body to prevent him from self-destructing.

"Don't be too rash"

A certain brown haired man holding a large mana imbued sniper rifle on his hand, said before shooting another Gastrea that came closer to the man.

"CHARGE!!!!"

A voluptuous and mature woman with long blonde hair and green eyes shouted. Pointing her large lance towards the thousands of Gastreas that was charging towards their base.

The hundreds of calvary behind him all shouted in response before charging at the army with their spears positioned in front them. Ready to skewer the Gastreas in their intial charge.

"R-Ria-sama"

The man from before muttered in disbelief since he didn't expect to see of the colonels of the Forsaken Faction in this small battlefield.

"ARGHHHHH!!!!!!"

All the calvary shouted, causing the Gastreas to shift their attention from the man towards the army that was charging towards them.

They all then shrieked in response before charging towards Artoria's (lancer) direction.

"[Releasing light from the end of the world...]"

She started casting without stopping her charge towards the opposing army.

"[That which pierces the sky and connects with the earth]!"

"[Anchor of the Storm]"

She muttered as her lance started to release brilliant golden light that circled around her lance. Emitting an extreme pressure that seemed to have no effect to her allies, but forces her enemies to stop in their tracks.

"[Rhongomyniad]!!!"

She shouted as she arrived in front of the army of Gastreas, causing her lance to illuminate bright light. 

"DISPERSE!!!!"

All of the lieutenant under her command shouted, causing the hundreds of calvary to split up. Artoria (lancer) then charged inside the enemy's formation, easily breaking through as the light of her spear easily shredded the Gastreas in her path to pieces.

"KILL THEM ALL!!"

All of the lieutenant shouted as they saw Artoria (lancer) successfully break through their formation.

The Gastreas all shrieked in response before getting trampled by the hundreds of calvary that Artoria (Lancer) brought with her. Most of them getting killed by the spears that skewered their bodies.

"A tier V Gastrea at the front!!! Everyone avoid-"

One of the lieutenant shouted but froze when the Gastreas that he deemed as somewhat of a threat, burts to smithereens in front of him.

"That arcane sniper sure is something"

He muttered before continuing his pursuit. Ignoring all of the Tier IV and V Gastreas who all burst one by one.

"[Boost]!"

The gauntlet in the brown haired man from before, loudly stated as another bullet of pure mana formed within Issei's rifle.

"6 more to go..."

Issei muttered as he aimed his gun towards the extremely large Gastrea located at the back of the army. Shooting it precisely at its head, blowing all of the organs from its abdomen up to its head into mush. Splattering it all on the remaining Gastreas on the ground, which were all being trampled by their chivalry.

*ROAR!!!!*

Loud roars suddenly echoed from above them, causing Issei and the rest of the army stationed in the fort to look up. They saw 100 fire dragons fly towards the battlefield.

"He came here pretty quick"

He muttered with a light grin on his face before focusing his attention back to his killing spree.

"Kill the Tier III and IV Gastreas at the back of the army!!! Lower the dragons!!"

An 6 year old boy with short blond hair and golden eyes filled with confidence that was very unlike for a child of his age.

"Arthur!?!? What are you doing here!?"

Artoria (lancer), his half-mother, shouted in surprise as she immediately recognised the voice of the young man on the dragon.

"Don't worry, mom! I can protect myself"

Arthur, Lucias' son together with Artoria, assured with a smile on his face. The dragons then started to breath out fire from the back of the opposing army. Killing all lower tier Gastreas in the process while severely injuring the higher tiered ones. 

"Advance!!!"

The lieutenant shouted as soon as they saw the opposing army lose composure due to Arthur's sudden attack from their back. Suppresing the army completely as Artoria (Lancer) and her chivalry killed the remaining Gastreas on the ground.

"VICTORY FOR THE FACTION!!!"

The army shouted as they killed the last Gastreas who came out of the dimensional rift. Having no casualties due to their experience in killing those beast for the last 5 years.

It's been 5 years since the war started, and unlike most of their expectations of ending the war early. Both sides didn't expect to hold on everyday under endless bloodshed.

The invader's army boasted numbers, while the alliance boasted strength. This caused the war to continue for 5 whole years. And as the war goes on, the alliance only became fiercer at each battle.

In the first year of the war central and south America fell, and became the main location of their enemies base. Creating a massive headache to the alliance as a result.

"You! Why did you come here!? Do you know how dangerous this place is!?"

Artoria (Lancer) scolded Arthur who had his head down with a guilty expression on his face.

"I'm sorry... Moms and Dad hasn't been able to come home lately because of this war... and my little sisters are sad so I want to help..."

"You... Arthur, even if you wanted to help. Do you know how dangerous your actions are? This isn't a place where you should be. You're still young so just stay at home, and watch your siblings alright?"

Artoria (Lancer) said with a slightly stern voice before hugging her half-son in her embrace. Burying his head between her large chest.

"We'll try to visit you more often, so don't do anything something as dangerous as this in the future, alright?"

She said, even though she herself fully knew what Lucias' and their children were capable of. They inherited a portion of Lucias' powers and abilities so they are by no means weak. But they all lack experience, and are still young. That's why Lucias, and the girls forbid all of them from participating even in small battles. Not until that Lucias could assure that they could protect themselves.

"Mn"

Arthur obediently nodded his head while Artoria(Lancer) gently patted his head.

"Let's finish this and go home"

Artoria (Lancer) said before throwing a single jet black cube to the dimensional rift. 

As soon as the cube made contact with the rift, it released hundreds of mana strings that covered the entire rift. Slowly shutting off the rift completely.

This device was made thanks to Void, who later joined the alliance due to the sheer destructiveness that the invaders have caused to several dimensions. It work simply as a kind of connection to the Void's realm, where she can manually fix the damage done on the walls. The only problem is that the cube must be fixed into the rift without any intermission nor movement for 10 whole minutes.

This made it difficult to completely close the rift without them wiping out the opposing army. Which is difficult since they come wave after wave. Especially around the borders, where many of the more powerful ones come out.

"Let's go home"

Artoria (Lancer) said as she placed Arthur on the ground and placed him on top of her steed. They then begun to ride back to the fort.

"Mom, can't we just teleport back?"

Arthur asked, causing Artoria (Lancer) to point her finger on the sky. Towards the large net like formation that covered the entire atmosphere around Earth.

"What's that?"

"It's your father's power. It was made to forbid anything or anyone to be transported using any type of spatial magic... this applies to both his allies and his enemies"

Artoria (Lancer) explained. It's been 3 whole years since Lucias erected the large formation that covered the entire world. The only reason why he has done this is to prevent the Gastreas and Demons from ambushing them since they all began to develop spatial movement and magic skills. The main reason why Central and South America fell, despite being heavily guarded.

"Mom... I want to see dad"

Arthur said causing Artoria (Lancer) to gently caress his head.

"So does he, Arthur... He wanted to see you all"

-with Lucias-

"Lucias-sama, when are you planning on attacking them? We can't just stay on defensive! We will lose more men if this continues on!"

Zeus said with a grave expression on his face, causing the other representative in the meeting room to nod their heads in response.

"I would if I could, Zeus. But if we split our forces, we would lose more territory to those insects. Our forces are already spread out far too much, if we split them more, then we will only weaken our defenses. Have you forgotten how endless their number of forces are?"

"..."

Zeus remained silent since what he said was true. Even though they killed millions of their forces for the last 5 years. It seems like they never run out and just continue to launch an increasingly fierce attacks towards their territories.

"We will first close all of the dimension rift in our countries, and find out why are there numbers not decreasing. If we can at least cut off most of their entryway towards our dimension. Only then can we attack them from their own dimesions. I already sent someone to gather information about their dimensions. So until they arrive, we remain defensive and try to limit the amount of casualties we experience"

Lucias said, causing Zeus to sit back down on his seat.

"Our forces are more powerful than them, but they outnumber us. They can launch kamikaze attacks on our territories without hesitation, so we have no choice but to remain defensive for the time being. Unlike them, we can't replenish our numbers"

He said before placing his hand on the world map on the table.

"If we can shut off all dimensional inside the borders. Then we can proceed to take back central and south America from them. I'll send my forces to aid you all in those locations so don't consult the enemies until then"

He said before looking at the representative of the humans that was seated at the corner of the long table.

"Any problems with the humans?"

"No... It's just that we lost too many soldiers in the last 5 years... The people started to question whether or not we can win. But you don't have to worry since most of them know themselves that the war is inevitable... only a few advocated to stop the war"

He said causing all of the representative from the Mythologies to look at him with a weird expression on their faces.

"Advocate for peace? Like we could negotiate with mindless killing machines. They will only become lunch for them if we stop the war"

One of the representative said while Lucias sighed in response. If only he had found out a way to close the rifts permanently earlier, then they could've kicked them off their dimension long ago.

"... Talk with your people and fix this. I understand their desires, but it is impossible for "peace" to happen when those insects are here. I think that humanity isn't so ignorant to not know that fact, right?"

Lucias said before glancing at the representative gathered around the table with a serious expression on his face.

"We'll immediately begin the plan by tomorrow, so prepare all of your troops. We'll go on a full scale attack on the dimension rifts in our territories by tomorrow"

He said causing all of them to nod their heads in response. 

"If you don't have any other questions. Then we'll dismiss this meeting. All of you go back to your stations"