DOOM in Adventure Time @emerald
True Chapter 3: The Slayer saves others

?/?/ Finn (Age: 18)

The scene now showed Finn, in his demon slayer armor as he continues his trek through the place he was in, he was shooting any hostile demon in his sights, freeing prisoners like humans, sex demons, Vampires, and even other demons who were more or less not hostile… the reason for this was that Finn was in a Corrupted Demonic base and some demons who were hostile had green flaming bits on their bodies and while some were hostile and were on the corrupted side, some were not and Finn made sure to have his helmet outfitted with various scanners and what not so he could tell who was hostile and who was not.

This pretty much allowed Finn a 0% friendly fire mentality since he knew who was allies and who wasn't.

There was also other hud based items in his helmet's visor and one of them pretty much gave Finn the reason he was here.

Save Ruby

That's right, Ruby, Emerald's daughter was somehow in this base captured and knowing what Finn knows… he was fucking pissed and he was fighting his way up the tower to save her… how she got here was a mystery to the readers so why don't we have another flashback to the past to learn more about Finn as he grew and to set up this demon hunting session.


Ooo/ Protected Island/ Finn (Age: 4)

Finn at this time was laying in bed, the time frame was a few days after he watched his mother get raped by that Corrupted Nightosphere Knight… right now he was having a pretty bad nightmare and was remembering the many people killed by the demonic beings and was muttering in his sleep as his rage grew in his sleep.

"No… no… I-I'll… kill them… kill them all…" Finn muttered while the scene went into his head during the dream as his rage grew, though as his dream got worse when the dream version of the CNK was reaching for his mother, the dream… oddly froze for some reason, so much so that even though Finn was shocked enough to wake… he didn't and looks around when he was oddly in control of himself as he wondered why everything was frozen.

Though a chilling voice behind Finn got his attention.

"Huh, so this is the one who gave off such rage?... well considering the dream I had the Cosmic owl freeze and what not, makes sense." The voice said and as Finn looked back and to his shock… he saw a large skeletal man with a bull or cow like skull minus the horns and he looked like he was in a… Gardener outfit?

"U-Uh… who… are you?" Finn asked while the being grins.

"I'm what you mortals normally meet at the end of the line… Death." Death explained while Finn's eyes widen and he starts to scream and comically run around as Death sweatdrops.

"NO!, I'M TOO YOUNG TO DIE!, MOMMY ISN'T EVEN AWAKE YET!" Finn yelled in his dream before he got wide eyes and looks at Death with a surprising amount of rage in his eyes which surprised Death as Finn got in a really poor combat stance.

"I-If y-you a-are h-here f-for m-mommy… I-I won't… l-let y-you go." Finn bravely said as Death looked amused by Finn's protective nature.

"Easy there kid, your mom isn't going anywhere, if she was I would have done it long ago, nah you mom is recovering and will be awake in a few years, two at the least if things go well… no I'm here to speak with you since I need to make sure you don't kill demons ad infinitum when you are older without some rhyme or reason." Death said while Finn looks confused and tilts his head in confusion for a moment.

"Huh?" was all Finn said when Death figured a 4 year old wouldn't know what ad infinitum means and this caused Death to sigh as he clarified himself.

"You… when you are older… shouldn't kill demons at large… without reason."

"B-But those demons harmed my mommy!, why shouldn't I go and get rid of them all!" Finn said though Death tapped Finn on the head and knocked him on his back.

"Simple… are all demons like the ones with those green flaming bits?... look closely… even if demons are unnatural to you… do you think a guy like this looks normal for a demon of his species?" Death said when he points at the Dead CNK's skull.

"N-No?" Finn said while Death chuckles a bit.

"You are right on that… simply put Finn, these are not the normal demons you know, they are corrupted into following the orders of another and lets just say that some are not and join willingly… tell me do you know how all of this came to be?, this island, the protection, many things that pretty much have you humans watched over as an endangered protected species." Death said as Finn looks confused a bit.

"N-No… all I heard from M-Mommy was that many bad demons came and harmed many humans in the past and now were like this because of some bad people making a big mistake or something." Finn said while Death hums.

"I see, guess Emerald and Morlock filled people in every now and then." Death said before he shrugged his shoulders.

"Anyway kid, long story short, because of how humans caused Marceline to go along her path, I'm here to make sure you don't go down the same path and try and kill innocent demons, plain and simple kid, not all demons are pure evil and if you say you think that… try and remember Emerald and Lillum and their daughter are demons… you going to kill them as well?" Death said while Finn wanted to speak… but thanks to how nice Emerald, Lillum, and Ruby were, Finn couldn't argue against that simple logic… some demons were good, some were bad, and some inbetween.

"Besides, if you want to get rid of all demons, you might as well be a monster to the rest of Ooo if you want to be an enemy to those not human." Death said while Finn looks really confused now, so much so that he had comical swirls for eyes… hey this was still a dream and anything was possible so swirls were just a simple thing and Death chuckles at that.

Once Finn recovered, Death explained that in many villages for humans, there were about 500 or so humans after their population rose over the years and the earth or Ooo as it was called now was more or less a world for non humans now, humans were not on top of the food chain anymore.

In fact Death explained to Finn that thanks to how the world was, the Candy Kingdom, Fire Kingdom, Slime Kingdom, and the occasional Kingdom that was Demon allies were the top of the food chain more or less and unless Finn played his cards right, humanity could either regrow back to its former glory or fizzle out like a candle about to burn its last.

That really bummed Finn out a bit when he heard that though Death did suggest an alternative of sorts.

"Anyway Kid, while my story is on humanities decline is depressing and I would say that this is just the natural course of things since Humanity pretty much bit itself on the ass with the Mushroom war and pretty much causing Marceline to go on the warpath with her demonic horde but there are a few upsides that you can take from this… for example thanks to the backup you have from Emerald and his family, the rest of you humans are pretty much guarded well though given enough time those corrupted demons may come back and who knows what will happen…" Death said while Finn looked more confused but got a angered filled look on his face.

"Like I would let that happen!, I will get stronger so I can protect mommy and everyone else good!" Finn said which amused Death a bit.

"Very well, just remember that you said this, which is why I came here aside from a bit of a talk on who your real enemies are, simply put not all beings are pure evil though corrupt beings… nine times out of ten unless they are willingly going under the control of whoever is in charge of them… point is try and only rip and tear beings apart who are hostile to you, self defense of sorts… but also with a couple gifts since you are a mortal who could use them if trained right." Death said while Finn blinks a few times at the gift part.

"Gifts?" Finn asked as Death smirks while the scene momentarily went to the present.


Present/ Unknown Corrupted Base/ Finn (Age: 18)

Finn as the Demonic Slayer was pretty much working up to a higher level of the base and he pretty much left carnage in his wake, he used his left hand when he was low on ammo and a moment later he summoned a human skeleton that had a sword and shield and it ran around to pick up ammo and what not for Finn so he could focus on the demons.

This resulted in Finn using the last of his shotgun ammo on a Corrupt Nightosphere knight and more exactly in the area where its dick would be and as it screams in pain after it fell to the ground, Finn's memories of that night his mother was raped was being brought up as he worked his way up the base and used his heavy armored boot to put this CNK out of its misery… he didn't feel sorry for the guy, he was just annoying Finn right now with the screaming and that attracted more enemies though Finn just blasts them with more ammo.

The skeletal minion managed to gather plenty of ammo and while Finn could use his own energy as a substitute for normal ammo, he would get slightly tired out if he used too much energy so unless it was an emergency he would try and not use his demonic energy for his weapons aside from two of them… one was the Crucible… a sword known to produce its own Nightosphere chaotic energy but its long since lost its power and Finn found this during one of his adventures to hunt corrupted demonic bases so Finn used his own as a substitute and the other… the shoulder mounted gun on his shoulder… this was shown to be a more advanced BFG of sorts when he turned to aim the shoulder mounted death cannon down a hallway and as the Skeletal minion took cover to avoid the bullets death radius, Finn launched the ball of deadly demonic energy towards a door that opened and inside were a horde of demons ready to attack Finn and Finn's helmet did calculations on aim and if it was safe to even fire it since Finn had to be sure he wouldn't accidentally hit Ruby if she was inside of the room.

Though to their shock they were instantly destroyed when the ball of Demonic energy soared over their heads and it made a small stop in the middle of the room to make a concussive blast of demonic energy which would have cleared out any survivors in the room… it didn't have as much power as the BFG 9000 but damn did it help in tight spots when he needed it.

Though thanks to the lack of power in the BFG 18000, a demon close to the door survived but it was barely alive… Finn didn't mind since he needed more ammo and he summoned a chainsaw of all things as he approached the demon which was a simple zombie like demon, a human turned into a demonic being and Finn had no sympathy since this guy seemed pretty aware… unlike others which caused him to mercy kill them… this guy however screams in agony as Finn used the chainsaw to cut between the demons legs, castrate him and slowly went upwards to cleave the demon in two while blood and intestines spilled out and Finn was covered in blood.

As that happened the body glows as was the chainsaw and this chainsaw was designed to not only rip enemies apart but thanks to special enchantments, it would allow Finn to not only gain ammo from defeated demons when the enchantment turned the flying bodies chunks into ammo, it also restored his health as well when the demonic energy of the demon being hit by said chainsaw of DOOM starts to break down and flow into Finn.

This allowed Finn to work his way deeper as the skeletal minion followed Finn and worked to either take on small demonic enemies, gather ammo from nearby and bring it to Finn, or save any captive humans, demons sexual or not, and the occasional Vampire.

Aside from coming here to save Ruby, Finn was also here to help as many beings as he could who were not hostile, unlike a different Dimensions take on a Slayer who pretty much showed no mercy to anyone not a human… Finn was more or less a one chance kind of guy, if he fought a demon, unless the situation required him to be merciless he normally would give some demons a chance to leave and he would let them as long as they didn't pose trouble in the future… sometimes it worked, sometimes it didn't… for those who attacked Finn… not many lived to tell about that.

In the rarely living demon survivors cases… it was because Finn could tell they were forced and only subdued them so they could get free later.

Thanks to him pretty much being raised by demons and his mother over the years, while he was highly protective of his human brethren, he also considered himself somewhat of a demon… he could fight them, instill fear from how ruthless he could be, and even go toe to toe with some of the strongest demons around for the most part… he still had yet to fight beings like Marceline though he would deal with her later… although as for the reason why he would fight her given that Finn knew these Corrupted demons were not on her side was still a mystery for now, it was clear Finn was on a warpath to get her but he had to gain strength and power to do so.

This pretty much resulted in Finn growing up and training his ass off once he got older, he knew a few demonic spells thanks to his lessons from Emerald, Lillum, and a few other allies of Finn's, while he was a freaking one man army who could rip apart many demonic allies, he did have help in occasional missions like his skeletal minion for ammo gathering as an example.

But enough of that with the exposition, Finn with his skeletal minion entered another room and Finn frowned when he saw a few corrupted demons had hooked up some Succubuses to some kind of draining machine and while they didn't look harmed they looked rather weakened, thankfully the corrupted demons in the room were few in number, most likely from Finn ending most of them on the way up but after he ended the demons, he freed the Succubuses and while none of them were Ruby, three of the 10 he freed were so low on energy from getting drained that as the other succubuses fled in fear, Finn sighs and looks at his skeletal minion and summoned one more which got the succubuses attention when Finn did that.

Finn then gestured for the Minions to go to both exits and passed them a weapon each, Finn had a super shotgun which he passed to one Skeleton and passed his rocket launcher to the other, contrary to looks aside from having their energy halved since Finn summoned two minions, they were sturdy enough to not get blasted back by the recoil and after they went to guard the room, Finn turned to the drained Succubuses and reached for his helmet.

A moment later the three succubuses blush when they saw that Finn had shoulder length blond hair, plenty of stubble for a epic 5 o'clock shadow and had a scar running down his left eye though thankfully it didn't seal the eye shut or injure the eye while he gave the three ladies a calm smile.

"Don't worry, I'm here to help… name's Finn, Finn Campbell, anyway I have some questions to ask you nice ladies, depending on the answers I could… help with your issue." Finn said while the succubuses blush at the deep tone of voice Finn had.

"W-What?" One succubus asked when she was curious about the questions, she had a shapely body, most shapely of the trio with D cup breasts and wide hips, the middle sized one had B to C cup breasts and was slightly thinner, and the final one was really petite at A cup breasts and thin hips, all in all this succubus looked the most drained of the trio.

"Well I want to know if a succubus of high standing was brought here, Ruby Ranmyaku, Emerald's daughter…. She is my girlfriend." Finn said while the succubuses looked surprised.

"T-The princess...Y-Your girlfriend!?... well… not sure on time exactly, when we are put in those machines it hard to tell time but thanks to the occasional… feeding if you can call it that I know she was brought here a day ago… maybe two if I passed out and didn't wake for a while." The most shapely of the trio said while she shuddered at the feeding they had and Finn could guess it was mostly unpleasant either in how it worked or tastes for them.

"I see… guess I don't have too much time then… they would drain a lot in one or two days…" Finn said while the other medium sized succubus speaks.

"Actually I saw her as well, seems they had to bring her to a special cell a few times when she overloaded the draining machine and they had to take time to repair it and stuff, apparently she was trying to break it by forcing too much energy into it but she was just taken up to the top floor an hour ago… she looked pretty healthy though." The medium sized succubus said as Finn hums.

"I see… alright I got one final question… can you three move at all or not?" Finn asked while the three succubuses looked at one another.

"Well I can walk." The healthiest succubus said while the medium succubus said.

"If I get some support I can limp out." The medium sized succubus said while the weakest looking shakes her head.

"No… I can barely feel my legs." The third said as Finn takes a second to breathe.

"Alright then, looks like I have no choice." Finn cryptically said which confused the succubuses for a moment before they blush when Finn reached for his codpiece and when he pulled it away his cock sprung free… seems it was either all natural or a mutation or given by Lillum as a gift with a size increase but Finn's cock was over a foot long, maybe longer and 3 in width.

The three succubuses, starved to hell and back drooled a bit from how massive Finn was and the demonic energy he emitted from his cock really caused the three succubuses to get turned on instantly, but given Finn was in a rush, he didn't have much time for some long romantic actions so with a quick spell he learned for some light telekinesis so he could bring a few boxes over, he picked up the three succubuses next and sets them next to one another with the weakest in the middle.

"Sorry but can't do much for foreplay so might as well do this." Finn said as he removed his gloves magically and he went to finger the healthiest and the somewhat weakened succubus's folds while he went to eat out the weakest and the trio groaned when they could feel a lot of energy enter their bodies just from the fingering and tongue work alone.

"O-Oh fuck!" The weakest said as her body looked a bit healthier already when Finn sent more energy to her then the other two and her body filled out to a B cup breast like state with wider hips, the second weakest got a size increase from B to C to around D while her hips looked more rounded and the final strongest of the trio went from D cup to E and her hips looked more rounded but not as much as the other two.

All in all Finn worked to give them more energy then pleasure but knew this wouldn't be enough and since he was in a rush, after making sure the trio were soaked, Finn removed his fingers and tongue from their pussies for a moment.

As the trio of succubuses recover from that sudden energy spike that they had, the weakest succubus looks down when she felt something touch her pussy lips and with an excited look in her eyes that had a stronger look in them, she moans in a pleased way as Finn thrusts his cock balls deep into the succubus's pussy and more energy was sent to her through Finn's cock while the other two succubuses blush at the sight as Finn starts to fuck the Succubus hard from the get go and she screamed in pleasure when Finn didn't hold back, forget adjusting, forget sensual lovemaking, Finn was acting like a beast right now just for his own pleasure and while the succubus looked healthier and looked almost as healthy as the strongest of the trio, Finn's orgasm was slowly approaching and he leaned down to suck on the right nipple and the two succubuses blush as they watched their friend get a fucked up look on her face as Finn pretty much got her from empty to full power in no time healthwise.

All in all it took just a minute and 30 seconds of intense fucking since Finn was in a rush and after a few good thrusts when he wasn't even trying to hold his orgasm back, he roars when he pushed his cock balls deep in the Succubus's pussy and womb and filled it with his sperm which caused her to groan while she had a fucked up look on her face when she was filled with more power then she would thought possible while the two Succubuses were dripping wet now as they watched Finn lean back and grins at her.

"Hehe, sorry for the rush but can only give one good climax per lady for this situation, if you want more later, can tell you the coordinates of the place I live so we can have more fun later… for now need to help your friends here so rest up, who knows, if I finish fast, could give one final shot for all three of you to enjoy." Finn teased while he grins at the succubus while winking at her and as she blushed, Finn moved to get to the second weakest succubus while she blushed at Finn and a moment later, Finn had her facedown on the box she was on and as the Succubus's ass was seen, Finn grins as he licked his fingers and fingered her ass for a moment and this really caused the Succubus to groan.

It took 10 seconds for Finn to stop that after he really roughed up the succubus's ass with his fingers alone and when he did, he moved to aim his cock at her asshole and a moment later, Finn pushed his cock balls deep in the Succubus's ass and she groans with a tongue hanging out of her mouth as Finn fucked her ass hard and fast without mercy, he even smacked her ass hard a few times when Finn enjoyed himself a bit even if he was rushing to fuck the power into these succubus's… he would change that later when he had some down time on the Island.

For now though he continues to fuck the succubus up the ass while the third and first succubus blush when the saw how strong Finn was, even after giving so much energy they saw that Finn was barely weakened at all from his actions, the succubuses would have thought Finn would die or something but with how much demonic energy he had naturally absorbed from around him, he was going strong and in no time he was fucking the succubus up the ass without mercy as his dick pretty much reshaped her insides and the look on her face told her she fucking loved every second of it.

Finn keeps his thrusts up while his cock barraged the succubus's ass constantly, this pretty much lasts a good minute or two as Finn's orgasm gets close while he had a strained look on his face, thanks to the earlier orgasm his ejaculations were getting farther apart and when he was about to blow he quickly leaned down and gripped the succubus's breasts and thrusts his hips balls deep which pretty much caused her to climax with a whorish moan as Finn growls when he blew his load up the Succubus's ass and she moans more when her orgasm was strengthened thanks to her absorbing the sperm for power and like with the weakest succubus her body became more filled out thanks to the sperm and she looked as heathly as the first Succubus.

After Finn rides out his orgasm, he pulled his cock free from the Succubus's ass and she groans from the feeling as a little of Finn's load that survived leaked from her and Finn chuckles when he pats the succubus on the ass and he looks to the third one and he had to catch her when she used a burst of energy to jump in Finn's arms while he had his hands on her round ass and she grins at the human.

"No need to wait on feeding me handsome!, give it to me good!" the healthiest succubus said when she teasingly rubbed her folds on the cock under her and Finn shrugged when he lifts her and as his cock was aimed at her folds.

A moment later, Finn dropped the succubus onto his cock hard and her folds took his cock eagerly and the succubus groaned when she felt her folds getting stretched wide and filled with demonic energy from Finn when he just fucked it and filled her with some energy to be safe.

This pretty much resulted in Finn lifting and lowering the succubus while he thrusts his hips and his cock barraged her pussy again and again while the sucucbus moans and groans with a fucked up look on her face when she loved the feeling she was getting, the other succubuses look at one another and they both used their healthier state to float over to Finn and used their hands to rub his arms and one succubus, the former weakest, kissed Finn on the lips which surprised him but he went with it to make out with the succubus as he fucked the healthiest more while she gripped the back of Finn's next while making sure not to headbutt her friend.

This pretty much resulted in Finn going all out in fucking the healthiest succubus for a minute or two, nearing three minutes and he gave a few good thrusts when he pushed his cock balls deep in the Succubus's pussy and came hard in her womb and Finn groans into the succubuses mouth that he was kissing and the succubus he creampied moans when she came hard on Finn's cock and as the duo ride out their orgasms the second strongest went to lick Finn's cock where the sperm was leaking and Finn shuddered when he rides out his orgasm and takes a second to pant for breath.

Though the succubuses seemed to want another load with some cute begging from the trio so Finn had to do a compromise of sorts since he couldn't stick around much longer and he couldn't let the succubuses suck him off three times so he let them do it all at the same time, the weakest sucked him off vigorously, the healthiest licked his balls and the second healthiest went to lick one side of Finn's cock and stroked off what the weakest succubus held back on getting there so her friend could have fun as the trio got more energy.

Finn groans as he watched this as the second weakest and healthiest alternated on what they did and sometimes both went to suck his balls, but when he felt his orgasm getting close, he gave a warning and in no time the trio were knelt next to one another as they worked to stroke Finn off while he looked down as he felt his orgasm getting closer and closer right before he groans as the weakest aimed his cock at her face to get a couple shots… then the second healthiest got a few good shots and the healthiest got one final but very thick shot of sperm and Finn pants as he watched the succubuses licked and kissed one another clean though as he got ready to go, the former weakest stopped him and took a second to suck his cock but instead of sucking it, she cleaned his cock off and after a few seconds, pulled her head off a fully cleaned cock and kissed the head of his dick with the other two doing the same when kissing his balls and after Finn got his codpiece and put his cock away, he watched as the trio were pretty happy with what just happened and as Finn got ready to leave when re-equipping his armor fully and summoned his skeletal minions to return his weapons.

Once he got them back, he cocked his super shotgun and started to walk out of the room to walk to the higher level though the three succubuses look where Finn went with hard to read worried looks as the scene fades to black.

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