Nicknames:

God of Decay
God of Death
Vessel of Malware
Malware's True Host
Rotting of the Multiverses
The Decaying Death
Extinction

Date of Birth: Unknown

Place of Birth: Alternate Alphaverse

Species: Skeleton God
Gender: Male
Height: 5'4
Weight: Unknown
Eye Color: Cyan

May I become the strongest in the existence that I will decay!-Extinction

Extinction is an extremely powerful and dangerous entity from the entirety of existence, and is one of the most dangerous entities of all time, as well as the most violent. He is a version of Maleare that has taken over the body of Reaper!Sans, the God of Death, and uses him as a permanent vessel, in order to spread his power in order to rot as much of existence as possible.

Backstory:

As this entity was once a Reaper!Sans, this means that he shares the same backstory as the original Reaper!Sans. He was created, along with his brother, Papyrus, by Gaster, the God of Magic, who used a dead star to lead to their birth, which is in context to the other gods, who were born from a star that is still alive. As there is too much living beings left in the Earth that they lived on top of, Reaper and Papyrus were created for the sole purpose of balancing Life with Death. While Reaper does do his job, alongside his brother, he hates it with every passion of his being, but understanding the importance, despite his opinion of it, he hides his thoughts very well, and holds back his opinions, as he knows that it will change nothing. He meets with Toriel, the Goddess of Life, and at first, she does not like his presence, due to being the antithesis of what she is, when she got to know him a little bit more, she realized that she is not that much of a bad person as she though, being surprisingly pleasant to talk to, though he can be a little bit negative at times and talk about some bad stuff that Toriel would prefer not to here. But other than that, they get along very well, with Toriel even beginning to develop feelings for Reaper, and in return, the feelings seemed to be a bit mutual. But Reaper also was caught in the attention of Geno at some point, and even began to fall for him as well, making what appears to be a love triangle of some kind.

But Reaper is not without some sort enemies of his own, one of them being Chara, who he messed up at and corrupted. And soon...it wasn't long before the Alphaverse starts to influence Reapertale, the universe that Reaper lives in. And then, on one fateful day, an entity of the Alphaverse, known as Infected, who appeared and awakened in Reapertale, came out of complete nowhere, and began to slaughter a lot of people, chopping their heads off and taking their souls, turning them into Wisps. Reaper, while a little scared of seeing Infected, due to how he looks, decides to step into the fight, and goes up against him, along with Undyne, Asgore, Toriel, and Papyrus.

The fight was extremely difficult, due to the fact that Infected was unlike any being that Reaper has fought against before. Reaper has fought against Error once, and he is one of the few that can match him. But Infected is simply more powerful than Reaper alone. But with the combined strength of every single one of the gods at full power, they were able to drive Infected away, and force him to get out of their universe. But that is simply just the beginning.

When the Alphaverse arrived, they began to invade his home AU, as well as countless AUs within his Multiverse. This affected the lives of innocence within the AUs very badly, but luckily, there are some good people that are trying to protect the Multiverse that is equally as powerful. It got so bad that Reaper Sans and the rest of his allies and brother had to bring all of their denizens into the Omega Timeline, which Core suggested them to do. Because of this, the members of Reapertale, even Reaper!Chara, as Core is friends with them, are forced to stay inside of the Omega Timeline, so that they do not get involved inside of the nonsense of Alphatale.

However, there are some points where he began to doubt about the safety inside of the Omega Timeline, as Error404 had gone inside of the Omega Timeline, and thus, Reaper had to keep his guard up in case Error404 did something. And he never let his guard down against him even once. But even when he is inside of the Omega Timeline, he still has his duties to fulfill, in which he needs to still manage the Underworld in Reapertale. Because of this, he would frequently go into Reapertale and go into the Underworld to deal with the souls, along with his brother, as he tries to aiding the afterlife. But over the years, Reaper!Sans has grown stronger over the years,  it just with age, but with the corrupted souls that he has reaped, as well as dealing with the threats of the Omega Timeline, which are mainly from the Alphaverse. And then, during the 3000 years of the Alphaverse, both Ink and Error had changed into very different people, with Ink gaining the soul of an Unnameable, and Error gaining the DNA of an Unnameable, and thus, they both became extremely dangerous threats, more so with Hollow!Ink, who now turned against the Multiverse and began to consume AUs in order to become more stronger then before. Luckily, Omnipotent kicked him out, but Reaper was still affected by what has happened, and began to fear for the worst of the Omega Timeline's existence. And then...the worst of the problems came, when Ten No Kami, the 10th child of MalesGrow, had came into the Omega Timeline, and began to wreak havoc. And too make matters worse, Error404's Mother, the Astral Mother, and 100, her eldest son, also came into the battle and began to wreak havoc alongside 100. Error404 and Error and Omnipotent tried to stop him, with both Errors fusing to make Error666, and with the aid of the TransVoid Beings, mainly Gabriel, who made Perfect666, they are able to defeat 100, and then, King Multiverse, he decided to go up against Ten No Kami, who is stronger then even Error404, but he is the best chance he has against them, due to the fact that Ten No Kami is able to manipulate and control those with Alphatale code, and King Multiverse, he lacks Alphatale Code, and is able to damage her badly. And during all of this, King Multiverse is able to finish off Ten No Kami with the MainFrame Cannon, which was finally able to bring down the child of MalesGrow. But the job was not done yet. Infected decided to consume Ten No Kami's head, which gave him a status similar to that of a Polothorn, and caused him to wreak havoc. Luckily, Marcy, an assistant of the Astral Mother, was able to return Error404, and loading killed him, in order to force him into his Butterfly form. They took the fight out of the Omega Timeline, as Reaper Sans could only watch in fear of what is happening. But unbeknownst to him, there was a TransVoid that is crawling to him.

Malware, the TransVoid Being of Decay, as well as the one that hosted Error404 and recently, King Multiverse, is now trying to find another host for him to use. And when he found another strong host, one that, while not as strong as the Alphaverse, is at least strong enough, he goes inside of Reaper Sans' body, as he decides to use him as a vessel. And that is when he realized something that he never thought was going to happen suddenly. He can feel his decaying powers amplified by Reaper's own powers over decay, due to the fact that he has a power that allowed him to embody death itself, for he had been born from a Black Hole, and thus, he can handle Malware's full power, as well as being able to amplify it, due to having similar powers to Malware. When this happens, Malware realized, Reaper can become his host, and thus, when Sol came and took the Conduit Souls of Balance and Destruction from Error404 and Infected, the entire Cycle that affected the Multiverse began to break, and the Omega Timeline got affected as well. Reaper Sans...he was almost affected as well...but the pressure simply knocked him unconscious, and Malware, he manifested through Reaper Sans' form, making him into a similar visage to Just404 and King Chaos, which is the form he took when he possessed King Multiverse. And thus, when the cycle broke, and the Omega Timeline is gone, Malware, possessing the body of Reaper!Sans, remained, still alive from it all. He looks around, and realizes that he can do a lot with Reaper's body...and as he now is able to control the darkness, the same one that Reaper can confirm form the Black Hole he was born from...he decides to use Reaper to go on a decaying spree. He then uses Reaper's power to travel to different Multiverses, decaying Multiverses and AUs that he finds more stronger then usual, which increased Malware's strength to insane levels. And thus, he decide to call himself, Extinction, in order to show that he is far more different and stronger then anyone else, amplified by the power of Reaper Sans' body and powers, his true vessel.

However, he would seem be stopped by Prism, who saw just how dangerous of a threat Extinction is. And thus, when Extinction and Prism fight, Prism was able to win against Extinction, but only with considerable effort, as he then takes him to the Edensphere, where he will be trapped for eternity. Imprisoned in the Citadel, he is locked in a high-security part of the prison, as Extinction is trapped in his cell, but he is not someone that will give up on the slaughter very easily. He is eating, patiently, until he waits for the right time...to break free. And when he is free...he will do whatever it takes to make sure that all of existence, will be extinct, by one of the strongest beings in all of existence.

Appearance:

Due to the fact that the vessel used my Malware is an alternate version of Reaper!Sans, Extinction is shown to still wear the black hooded robe, with a blaster skull in the rope at the position of the collarbone. However,  the robes look a little bit more torn than before, revealing his elbow and knee bones, but due to Malware using his body like a vessel, it's difficult for most people to realize that this is the case. The skull blaster on the neck is now black with a cyan-colored grin present, making a terrifying visage. And the face of Reaper, it is also black, with the face resembling that of Just404 and King Chaos, meaning that the face has sharp teeth and piercing eyes on a black skull, with the eyes and teeth being light blue in color. There are also images of eyes on the outer sides of the hood and on the sleeves of his robes, with the eyes being light blue at the sclera, the pupils are black, and the irises are white. His wings are also possessing black bones, and the wings, which are more darker then ever before, are drilling what seems to be black liquid from the tips of the feathers on the wings themselves.

Personality:

As he is the a version of Malware that is using a version of Reaper as a vessel, he is the single most violent entity of all of time. Appearing as the embodiment of violence, sadism, ruthlessness, and megalomania, Malware!Reaper, or Extinction, as he prefers to be called, is a ruthless, soulless, and codeless entity, caring more about become more stronger then anyone else, vowing to not be below and to be above, no matter what. He is a being that will make alliances, but only if it will best suit him, and will do whatever it takes to gain power, no matter what. And if the person's use has been used up, he will decay and kill them, as to make himself stronger a little bit more then before.

However, in spite of his violence and cruelty, he is not mindless in his pursuit. As he has taken over Reaper!Sans, and thus, adopted some of his personality, such as his sadism, he also gained his knowledge and has strong control over his emotions. Thus, Extinction has a level of cunning, strategy, and patience that is only rivaled by Error404, perhaps being able to surpass him in that regard. He is even more insane, due to Reaper having insanity within him, but he is now far more restrained and rational, and thus, is able to think of his next move, instead of charging in like usual.

Despite this insanity, he is now speaking in a time that is different compared to his usual speech. He now speaks in a soft spoken tone, and is able to speak in a polite way. But this serves only to make him sound more scarier then before, as his sadism sometimes laces into his tone. That way, it will unnerve the unfortunate victim enough that he is able to decay them without trouble.

Ultimately, Extinction cares about no one but himself and his own power, with his ultimate desire being the strongest being there ever was and decay them, for he will stop at nothing to achieve this. And with the power of Reaper being very similar, if not the same as Malware, he will use his body in order to achieve this goal, and he will do whatever it takes to destroy everything, and make himself the most dangerous and most powerful TransVoid Being of them all.

Powers/Abilities:

Decaying Death Aura: Extinction has a passive ability where the world around him will start to decay until life cannot thrive. The decay starts from Extinction himself, spreading infinitely at a steady rate until all life is dead. The ability stops when Extinction is gone. This ability comes from Malware, who is a TransVoid Being that is able to decay and rot anything, even entire worlds with just his mere presence appearing. He power is able to be amplified when gets enraged. This decaying aura is what allows Extinction's power to permanently grow. Only Conduits, TransVoid Beings and Unnameables, and the denizens of the Edensphere are resist the effects of the Decaying Death Aura.

Reality Black Hole: Extinction, using Reaper's power of manipulating the darkness, is able to make a black hole that is so strong that it can suck in Multiverses, and if continued long enough, can suck in the entire Reality that he is in.

Soul Sensing: Malware, due to using Reaper's body, is able to sense a person's soul, even if they are from another Multiverse. And since the Multiverse has countless lives and AUs, he is able to go and decay the AUs without trouble trying to find even the strongest once to increase his power.

Malware Blaster: Extinction can summon a black blaster that has black bones and cyan eye sockets with black pupils, which is able to fire a beam made of darkness that instantly decays the souls of those that are in its path. It summons by a series of black chains that comes out of Extinction's back, follow by the appearance of the Malware Blaster. He can also use the Malware Blaster to open its mouth and charge it, but so that it can use the darkness to make a black hole effect of some sort.

Malware Bones: Extinction can fire black bones that can instantly decay anyone that gets hit by them, and while touching can infect cause decay as well, that is only if it is touched for way too long. Extinction often uses the bones in order to make it difficult for people to go to him and attack him.

Puddle of Decay: From the wings of Extinction, black puddles are shown to form and gather to make a larger puddle. If a person steps onto the puddle, their life force will drain at a dangerously rapid rate. And if stayed on for too long, they will die from the decay of the puddle itself. It is stronger then Grim!Reaper's Death Puddle, as well as more dangerous.

Darkness Clones: Extinction is able to manipulate the darkness in order to summon clones that will aid him in battle.

Malware's Scythe: When Malware took over Reaper!Sans, Extinction manage to change and amplify the Scythe in his possession, now becoming a pair of scythes connected by a single chain that can extend either to infinite lengths. The scythe's previous purpose was to slay gods, but since Malware had taken over Reaper, he is now able to use it to slay and kill TransVoid Beings, and this time, the effect is permanent, as the TransVoid Beings no longer come back to life as if nothing happened. Instead, they are just killed off from existence permanently. The appearance of the pair of scythes is the same as Reaper's Scythe, except that the weapon is now darker, the Blaster on it is black, with the eye sockets that glow a cyan color, and the blade also is able to glow cyan.

Glare of Hades: If Extinction looks into the eyes of his enemies, the enemy will freeze in place, as they are now so scared that they are paralyzed with fear, l giving Extinction a chance to kill them with his powers.

Infinite Speed: Amplified from Reaper!Sans' speed, Extinction is now able to move so fast, that even Error404 cannot catch up to him. He also appears to be in 2 places at once when he uses it sometimes.

Flight: Extinctuon has a pair of wings on his back that allows him to fly up into the air, allowing him to cover more ground then before.

Omnipresence: It is likely that Extinction is omnipresent, as Reaper is claimed too he as such, and Malware is able to take over his body. 

Shadow Merger: Extinction is able to hide in the shadows of his opponents, and thus, he uses this power to sneak up onto people, making it perfect to be stealthy and go in for a swift kill. He also uses shadows to travel to different Multiverses and Realities.

Transvoid Whirlpool: Extinction is capable of contorting his body into a large mass of shapes as he continues to grow endlessly, and has a black hole effect on himself. If he were to ever sink any victim into the mass of which is his body, they'll be transported to the Transvoid where the monstrous beings and entities would most likely give you a fate worse than death itself.

Reality Apocalypse: Extinction's most powerful attack, in which he can summon countless Malware Blasters, and can fire blasts of decaying darkness that is capable of destroying the reality that he is in, as well as the reality that is close to the one that he is in. It can easily dwarf an entire Hyperverse without issue.

Relationship:

Error404: Malware's former vessel, he left him for King Multiverse, in order to change him onto Kong Chaos, only for King Chaos to not be able to sustain his form for a limited amount of time and gave up on him. He decided to consider Error404 unneeded, since Reaper proved to make his power more greater then before.

Reaper!Sans: When Malware left King Chaos, he is able to find Reaper Sans and possessed his body. But when he did, he sensed that Reaper can handle his power, due to the fact that Reaper is not truly alive, being made from a dead star, and the fact that his power revolves around death, and thus, is able to ability the power of Malware. Because of this, Malware decided to make Reaper is permeant vessel, and thus, he buried Reaper's mind deep inside of himself, and uses his body to go on a decaying spree.

Malware404: Another version of Malware that had taken over the body of Error404 permanently, Maleare404 and Extinction at some point met when he visited Extinction inside of his cell, and they both seem to get along, as when Malware404 helped Extinction be free, they used their powers to wreak havoc on the Edensphere, which had gotten them both in trouble for a lot of times.

Faker: In contrast to Malware404, Extinction does fear Faker, due to the fact that he is the most dangerous version of Error404, being rivaled only by Abaddon, or Dark404. Thus, he cannot face him yet, until he gets strong enough to go against him. For now, he leaves him be and does all he can to avoid him.

Prism: The one responsible for taking him out of his Multiverse and putting him into the Edensphere, Prism does all that he can to make sure that Extinction does not dare cause anymore damage and harm to the existence, in which he is that much of a threat to all and any that dares stand in his way, for he seems him as a dangerous threat that is matched by Malware404.

Notes:

Extinction is claimed to be so dangerous that he decayed and rotted countless Multiverses and Hyperverses, which made him currently as strong as Malware404.

In the Alphaverse that Reaper is in, there is a status called True Vessels. They are entities that are able to handle the power of a TransVoid Being and amplify their full power inside of their bodies, even if the vessel's body isn't strong enough. But for True Vessels such as Reaper, they can handle their powers without problem, and thus, Reaper is considered to be a true vessel to Malware, due to Malware's power being amplified when he took over Reaper's body. Other examples of true vessels is Eledora being able give Dream Sans his power, due to both being able to feed on positive emotions, with Eledora being able to feed on happiness and joy, MalesGrow being able to host Nightmare, due to them being the most cruel and villainous of their own kind, and Faringold to Dust, due to them gaining power from the innocent lives that they have killed, and Yesmerian to Core!Frisk, due to them both being omnipresent, which is just to name a few examples of True Vessels.

He is the most dangerous version of Malware, matched by Malware404.

Dark404 is aware of Extinction, and has plans for him.

Extinction is able to surpass the power of Just404 Butterfly.

Oddly, Extinction has a liking for coffee, but it is most likely due to the fact that Malware is able to gain some of the personality traits of Reaper Sans when he took over his body.

The exact number of Multiverses and Hyperverses that Extinction had rotted away with his power is unknown, but considering he grew enough in power to bring himself to be chained to the Edensphere's Citadel, it is likely that he is able to decay what must have been millions of Multiverses and Hyperverses in order to go to such an amount in the first place.

Extinction's Decaying Death Aura has no affect in the Edensphere, due to it being strong being to handle his power. The same applies to the denizens, although his other attacks can work on the entities if they hit them.

It is unknown what became of Reaper's mind when Malware had taken over Reaper to become extinction. But it is most likely that he is simply locked away in the back of his mind, as Reaper Sans is unable to die in anyway, and thus, is kept alive by Malware, while his body is used as a vessel.

As Reaper was born from a Black Hole, which is known to suck anything in, this made him a perfect vessel for Malware, as Reaper won't decay.