Chapter 1: First stage-Incubation.
In a rainy night new Domino we see a teal haired boy crying, walking down the street. This boy was named Leo who always felt like a outcast and alone. This day didn't go well for him as most of his friends heard a false rumor about them that someone spread and they all though it was Leo so they decided to all go and yell at him and stopped from being his friends. Also during that day he was suspended as he was rumored to have gone and vandalized the vice-principles office and for the rest of that day bad things kept happening to Leo but the worst thing was when he went to a meeting with the signers but after a while his own sister snapped at him for being an incompetent duelist and that maybe he shouldn't be at that meeting. Of course Leo then left the meeting and that was why he was wandering the streets crying. He eventually stumbled upon an alleyway and as he began to walk the world around him suddenly faded into black and Leo was trapped in a void of nothingness, he ran as fast as he could through the void tears streaming through his eyes, he tried calling out for help but nobody came. Eventually he fell on his knees and screamed into the endless darkness. When he looked up he still saw nothing. Leo just got up and began to walk until it seems that he would die when he heard a voice.
?: Leo.
Leo turned around and saw nothing.
?: Leo!
Leo: Where and who are you?
?: I am the one who rules the world before you.
Leo: W-w-will you hurt me?
?: Only if you strike me first.
Leo: What do you want with me?
?: Leo, you underestimate your true part with the signers.
Leo: Then you got the wrong person, Luna is the one-
?: I know of Luna, Akiza, Yusei, Jack and Crow, but you are more powerful then all of them combined.
Leo: Me?
?: You have the power to kill the crimson dragon itself.
Leo: Kill? Why would I do that? Who are you really!
?: I am the one who is known as the primal being.
Leo: You mean the king of the netherworld? The thing rex tried to use on new domino?
?: Not entirely, Rex wasn't powerful enough to truly wield my strength. I left him to play with the king of the newtherowld and crimson dragon. But unlike Rex You are worthy of using my power.
Leo: ...
?: You see, you are a catalyst for a grand scheme to finally end that tyranny of that dragon!
Leo: You're the tyrant! The crimson dragon cares about me!
?: Cares? HA HA HA, he only cares for his signers, he doesn't care about you.
Leo: I-I guess you could make that argument.
?: I can bestow you the power to get revenge on all who wronged you. I could help you show your friends that you are truly above them, I can help you make the signers suffer!
Leo then woke up to see it was daytime and he was still in the alleyway. He felt extremely weak and to the point where he fell onto the ground and he tried to crawl towards the street hoping to catch someone's attention but what he saw on the other side made him regret ever denying the voice. He saw the signers at a restaurant in front of him and not even questioning that he wasn't there. He tried calling for help but they fell of deaf ears. He then fell onto the ground and he finally made his decision.
Leo: I accept.
At that moment a glowing mark appeared on Leo's arm (The mark looks like the mark of the dragon's heart but as a dark signer). He then picked himself up and walked home
*the next day*
Leo woke up to a bright morning thinking what happened last night was only a dream but he then saw the mark. He began to realize that if the others found out what he's become then his plans would be compromised, he couldn't reveal himself yet, Leo quickly ran towards the bathroom and began to apply many ointments and lotions to try obscure the mark but there was no avail. The mark wouldn't stay hidden. Leo then went to wash the ointments off and as he began to dry of his arm he noticed that the mark could be obscured if a piece of clothing covered it so he long sleeved green jacket and sure enough it covered the mark. After that Leo went to school as he got a letter saying that the real person who vandalized the office was caught. Leo and Luna were walking through the school and were suddenly stopped by Leo's friends
Dexter: Hey Leo, it turns out we were wrong. Apparently it was someone else.
Bob: Yeah, we're really sorry.
Leo: ...
Dexter: Leo?
Leo: Get out of my sigh!.
Bob: What?
Leo: Better yet get out of my life!
Luna: Leo!
Leo: You all said it was me no matter what I said, but now since you found out otherwise you come asking for forgiveness!
Dexter: Hey man we sai-
Leo: Sorry doesn't fix the words you said. If you really want forgiveness duel me for it. Two-on-one!
Dexter: Uh okay.
Bob: Alright.
The three then went to the school duel arena and activated their duel disks.
(Leo: 4000-Dexter: 4000-Bob: 4000)
Leo: Dexter how about you go first.
Dexter: Okay, I summon batteryman solar!
Batteryman solar level 4
Light/thunder/effect
(1500 atk/ 1500 def)
Dexter: I set a card and end my turn.
Leo: *Draws card* You the funny thing about machines? They're useful for getting what you want! I summon viser des, why should I swiftly kill that monster when it can instead suffer for three whole turns!
Viser des level 4
Dark/fiend/effect
(500 atk/ 1200 def)
Bob: One low attack point monster?
Leo: Looks can be deceiving!
The monster then latched onto batteryman solar.
Leo: Viser des ensures your monster will be destroyed in three turns and he can't be destroyed in battle. But now since I control a monster I can special summon morphtronic injecten!
Morphtronic injecten level 4
Dark/machine/effect
(1600 atk/ 1200 def)
Leo: Now set two cards and I end my turn and since it didn't battle injecten deals you both 1000 damage!
(Leo: 4000-Dexter: 3000-Bob: 3000)
Bob: I draw-
Leo: I now activate Viser des's effect, the first turn is over so now batteryman only has two more turns to live!
I summon flamvell guard in defense position.
flamvell guard level 1
Fire/dragon/normal
(100 atk/ 2000 def)
Bob: I now set three cards and end my turn.
Leo: My turn *Draws card* I tribute injecten to summon byser shock.
Byser shock level 5
Dark/fiend/effect
(800 atk/ 600 def)
Leo: Byser shock's effect sends all your set cards back into your hand!
Bob: Oh no!
Leo: Also next turn viser des will destroy your monster so you guys better come up with something fast *Sets two cards* starting now!
Luna: Leo what's gotten into you?
Leo: I just grew a spine!
Dexter: I draw-
Leo: Viser des, kill that monster!
The monster shoved it's drill into the monsters head and destroyed it.
Leo: Well now, your monster is gone!
Dexter: Leo, you should now that solar is not the only monster in my deck. *Draws card* I summon batteryman AA!
Batteryman AA level 3
Light/thunder/effect
(0 atk/ 0 def)
Dexter: Since it's in attack position it gains 1000 attack points!
(1000 atk/ 0 def)
Leo: I activate skull invitation! Now every time a card of ours goes to the graveyard the player who sent it takes 300 damage!
Dexter: Then prepare for 300 damage! AA attack viser des!
(Leo: 3800-Dexter: 3000-Bob: 3000)
Bob: And you take that 300 damage!
Leo: You fool! I activate crush card virus!
Dexter: WHAT!
Bob: Oh no!
Leo: Yes, crush card sends all 1500 attack point or more monsters from your deck to the graveyard and because of skull invitation, well lets just say it's about to get painful!
Dexter sent 11 card of his to the graveyard and Bob sent 10 cards.
Leo: Now skull invitation finishes you both!
(Leo: 3800-Dexter: 0-Bob: 0)
Leo: ...
Leo began to walk away when he was stopped by his sister.
Luna: Leo?
Leo: ...
Luna: Are you okay?
Leo: ...
The two then went to class. As it turns out the vice principle was there and he was giving a lecture, however during the lecture Leo began to plan his next moves. Of course the vice principle saw Leo was zoning out and he then snapped at Leo.
Rudolph: Leo are you even listening!
The whole class turned towards Leo.
Leo: I am.
Rudolph: Then tell me when I just told everyone.
Leo: You were telling us about monsters and different types of monsters and better yet I will even get into their types, gemini monsters require to be normal summoned twice in order to activate their specified effects, spirit monsters are monsters you can normal summon with the catch that it's returned to your hand during the end phase, tuner monsters are monsters that allow you to perform synchro summons.
Rudolph: How? You were zoned out.
Leo: No, you simply assumed that, like you assumed I vandalized the office. The thing these two incidents have in common is that both times you were wrong!
Rudolph: That's it you will receive detention at the end of the class!
Leo: Really, I was correct was I not?
Rudolph: I don't care if you were correct!
Leo: Don't care that I was correct, isn't that what teachers teach us to be?
Rudolph: Grr.
*?*
The Crimson dragon was feeling strange, his chest was having a weird sensation but little did the crimson dragon know that an infection was brewing within him. But what the crimson dragon did know however was that a great crisis was about to happen.
*The facility*
Leo disguised himself in a cloak and entered the facility, there is someone he wanted to get revenge on that was here. He entered the facility undetected and made his way to the control room and opened the door to Sayer's cell.
Sayer: What?
He exited the cell and saw the cloaked figure go down a hallway and Sayer of course followed him and he followed the cloaked figure outside of the facility. Sayer then sensed that the cloaked figure was none other than a dark signer.
Sayer: Dark signer! You will pay for what your organization did to me!
Leo then turned around.
Dark signer Leo: Do you know who I am, or have you forgotten?
Sayer then used his psychic powers and figured out that the cloaked figure was Leo
Sayer: You're that kid!
Dark signer Leo: In the flesh!
Sayer: So you became a dark signer, I presume you're here to make me pay for almost killing you.
Dark signer Leo: Ding ding ding ding! Good answer Sayer. Now lets duel, but this is no ordinary duel let's play a shadow game!
To be continued
So I decided to write a fanfic based on Leo becoming a dark signer. If you guys are wondering why Leo, well he was so underused and was just a punching bag in the series, after all he only won against Aporia and Devack and that was with help so he never really had a win. So in this fanfic it takes the punching bag of Yugioh 5ds and turns him into something powerful. I do not own Yugioh 5ds this is just a fanfic.