Before we start, let me tell you that this story was inspired by other Fate/Series stories on many different sites. But, instead of Shiro or *ugh* Naruto, we will have the Main Protnagonists from Fate/Grand Order. Or more specific, my Fate/GO Virus in the System Universe.

So you can expect the best kouhai (tied with BB) Mash/Shielder and Ritsuka Fujimaru a.k.a. Gudako with her famous and terrifing Riyo Gudako personality.

Anyway, since this story will only slightly follow my stories Canon, there will be some changes. First, it will happen after the fight with Goetia and the events of Epic of Renmant, but before the Loostbelts. Of course some of the events will be done and Canon.

Second, Roman will be alive and we the MC's will Know about him being Solomon. Or more specific that he was Solomon, since he lost all of the traits of a Servant he had, finally making him a normal human. Fou will also be with them, but won't be that active. He will probably be hiden in Gaster's big breast pocket.

Third, some Servants will appear that that still havent made a appearance before they made it in Canon. Example, Anastasia, Ivan, Sigurd, etc. All Servants won't have screen time, but they will probably be mentioned at least once.

Other things will be shown in the chapters. Now lets go into other things. How will the story progres. So here is a small Summary of the events.

One day Roman called them all in the Control room to show them two things: that a Grail was detected in one of the Universes Gaster detected using his and Merlins skills. And that BB is missing. Again.

Anyway, Roman tasked Gudako, Mash and Gaster to gather some Servants and Rayshift to that dimension. But there was a small problem. Since Gaster had allready seen the dimension, he was unwilling to go. Which resulted in a giant game of hide and seek. After finaly managing to catch him, they gathered the Servants and went to the dimension, which Gaster decided to call DxD: Genocide of the Age of Gods.

SInce that was the First time doing a dimensional Rayshift, the Chaldea was accidentaly scathered in teams of 2, with Gaster ending up with Caster.

The story will start around the time the Fallen have kidnapped Asia, just so you Know.

Also the mayor changes this story will be some more realistic things happening. Which will be the start of a small rant.

Since Gaster needs to absorb souls (that is Canon, but later) for reasons only he, Merlin and Roman know, he is willing to kill other people for their souls. Of course he won't ever kill any Heroic Spirit or Chaldea staff, since that will destroy their existance. But, he can last for very long just by absorbing one soul.

Also since he is based on some Undertale characters, he will have some of their traits. Which makes me go a little deeper in the lore.

OK, since lets compare slightly the Fate Heroes and DxD Heroes. For example, if they have their full powers, top Servants like Gilgamesh, Karna, etc. could easily defeat 99% of the DxD cast. Now we go to a more deeper thing, by comparing Gaster to some stronger foes. We take a example of the Four Maou's.

If we compare Gaster at the beggining where, like Mash, he was still a novice in being a Servant, he would be defeated in no time. But since this one is the version after he completer the Singularities, he has more knowledge about his Skill and Noble Phantasm. Adn since there are some people who allready Know about what his Skill and NP do, they can agree with me that he could defeat them.

There are multiple reasons to that. The First one being that the Maou's probably didn't have a real fight since the Civil War, which happened around 2000 years ago. Do you Know how much that time is? No matter which being you are, in that time you will be rusty in real combat. Gaster on the other hand had to fight almost every day, with a few weeks free. And that is not counting the events.

The second is that Gaster likes to finish battles quickly and is a cheater. If Gudako tells him to defeat someone, he will do it in the quickes way possible. If he wants to fight fair and square, which is really rare, he will probably use every trick he has, no matter how low it be. The only exeptions are when he faces against a Heroic Spirit. Example; Karna. Gaster will try to fight without cheating, but will in the end use a few tricks. So, think of him like Robin Hood. Or even better, think of his style like Sans, with some mayor boosts.

The only reason why he fought againts Martha like the was he did was because the others needed as much as time to get away from her, with Gaster buying them time.

There is also the fact, like mentioned before, he will when facing a opponent he knows that Gaster can't defeat, he will use tricks and cheats. Example, faking to be defeated, making the opponent come near him and BAM, imaple him with a bone from Bellow. If he fights a person he knows he can defeat, he will probably toy with them slightly, before killing them.

That is also a factor. Gaster allways goes for the kill, which im sure some Servants also do. If he were to fight against a person who belives in honor during the battle, he will not wait for them to say anything. BAM, you have been impaled with a bone before you could even say something. That is just his style he uses after hours, even days of trying to learn his own personal fighting style. Which resolves around him going straight for the kill.

Next we go to another theme: the fact that this story will have some realistic stuff. Here is a example: Gudako. She saw what could have happened with the fight against Goetia. She learned to be more selfish, but she still loves and cares about everyone in Chaldea. She is willing to take drastic measures in time of panic. The same for Mash, she started to gain more will to do things. Overall, they start to behave like real people. But there will be also some comedy.

Now lets go for the Servants that will go with them. There will be two from each class. The First is the one that will be with the Chaldea group, the second ones are the ones under BB's control. I will also list the reason for the ones that are with the Chaldea group.

Saber

Here I was thinking a lot and eventualy decided to go with Lancelot., even if I wanted to go with Attila. The main reason is because of his skill with weapons. Not only does it make him dangerous with almost anything in his hands. Not only that, but from what I gathered, he can match Gawain while the Sun is out.

Archer

OK, here I was thinking of James Moriarty. You are probably woundering why him, when I could have picked someone like Gilgamesh, Ishtar, Robin or Emiya. Well, the reason is simple. He is a evil genius who is as smart as Holmes. That and also his coffin is fucking powerfull.

Lancer

I decided to go with Ereshkigal. The reason is so the Chaldea Team could match some God's in battle. Also, since she is the Goddes of Underworld and can use the souls of the dead, she is basicly a adorbale charger for Gaster.

Rider

This choice was fairly easy. Ozymandias. We can agree that both his Mesektet and his temple would serve as great bases. Not to mention that he himself, if we ignore his beasts, is pretty damn powerful.

Caster

Before you say anthing, hear me out. I choose Sieg because there is a pretty good reason. If we look over his Fate/GO counterpart, not only would we have Siegfried for a limited time, but also the dragon Fafnir. Also, Gaster goes pretty well with him since they both are "underaged". Sieg being alive no more that 5 year (even less) with Gaster doesn't have a actual age. Also, he has Plot Armor.

Assassin

This choice was rather easy. Ryougi Shiki. That is mostly because she lived around the time the DxD plot happened and would have the highest chances of belnding in. And her Mysical Eyes of Death Perception are OP as fuck. Hell, I belive not even Ophis and/or Great Red can survive them.

Berserker

There were many good choices but I choose Cú Chulainn Alter. If you remember of all the things he did in America, you shoul Know my reason. Also, his fighting style (no mercy) goes well with Gaster.

Extra

Here I had the biggest trouble. And still have. I don't Know which Extra Class Servant to choose. When I get a idea, I will post it.

If you guys have any suggestion for a Servant that could go instead for which class, let me Know which one and why.

Now lets go with the fact about realism. There DxD MC's have never trained, not sure about the past. And yet they still win. Here is a question: who would win if lets say Karna fights against the Gremory group or ORC. Some of you would say the ORC. And this would be your reason why: "because of the power of destruction/ booster gear/ etc." Well, do I need to remind you that any of those things can barely be ranked C, maybe a Longinus B. Karna's armor can take those attack head on. And the only reason Vlad managed to go against hi one-on-one is because of the boost he gaine for being in Romania. And the reason Sieg won was because he had the support of 4 other Heroes (Siegfried, Fran, Astolfo and Achilles). And there is also this fact, lets take Asterios for an example. His NP, his Labyrint is ranked EX. Which is also for good reasons, it creates his labyrinth, from which you can escape like that guy from his legend or Asterios giving you the map. So, you can except that people could easily die from it.

Now, the last point is pairing. SInce this story overall is a harem one, Y/N will have his harem. But I will also add some other pairings. Here are the ones that came to my mind.

Sigurd x Brynhildr

Roman x Quenn of Sheba

Kintoki x Shuten

Sieg x Astolfo

Gilgamesh x Enkidu (its not gay if its clay)

That's it for now. Don't Know which else are there.

Also that is for today. Leave a comment if you have a question. And remember, this is a AU so some changes from the Fate/GO plot are there.

See ya all next time. Peace out.