Nightmare!Sans

"Oh no Dear boy, I'm not Insane. Just a bit of a Sociopathic Sadist, that's all." -Nightmare responding to Dream stating he was Insane. Nightmare!Sans, or Nightmare!Tale Sans is The Secondary Antagonist of Chapter 1 of Custom-Verse, Specifically The Main comic. He's The Main Antagonist of Dream vs. Nightmare #1-3, and a minor antagonist in Ink vs. Error #2, Delta vs. Cross #1, and Anti-Virus vs. Virus #3. He is a Classic Sans corrupted by his hatred and The Negativity Apple

Story/Backstory
Nightmare Sans was originally just an Undertale Sans from a Genocide route. Somehow through his research, he encountered an alternate universe version of himself. That being Distrust Sans. (E.G., Underswap Disbelief.) The two of them teamed up to stop their respective humans. After constant fighting, they fled to different locations. The Humans eventually struck down Undertale Asgore and Underswap Toriel. However. After continous fighting, They reached a strange location in an alternate universe they didn't recognize. They found two trees. One of them had blue leaves, and yellow apples growing from it. The other, Purple leaves and black apples. Both trunks were brown, like an oak. Distrust Sans ate from the tree with the yellow apples, and Undertale Sans from the tree with The Black Apples. This turned Distrust Sans into Dream!Sans, and Undertale Sans into Nightmare!Sans. Nightmare and Dream successfully were able to kill the humans permanently... ish. After the humans died, they were encountered by the spirits of each tree. The Spirits explained how the two were now guardians of each respective trees. And since they both had nothing better to do, they obliged. After Five years, the two had a decent friendship. Nightmare was generally more antisocial, due to not only his intimidating appearance, but also surplus amounts of negativity. Eventually, two albeit familiar humans came to the trees. As it seemed, Undertale Chara and Underswap Frisk had been reincarnated, but without memory of the past events. Chara ate from the tree of Negativity, and Frisk from the tree of positivity. They became Nightmare!Chara, and Dream!Frisk. Dream was happy to see new people, and Nightmare was just happy to have someone to talk to. However, one time while he was talking to Chara about Papyrus, he began to forget more and more about *how* papyrus died. Eventually, The Spirit of Negativity heard about this, and used one of it's apples to make a replica. That became Nightmare!Papyrus. The Same thing happened with Dream!Sans. Eventually, he was able to describe his brother enough that The Spirit of Positivity made a replica, Dream!Papyrus. This pattern continued until everyone who had died from each AUs' respective genocide routes, was now alive again. As it seemed, everything was perfect. However, eventually Dream got overly popular with the common folk. The common folk eventually directed all their problems to the Nightmares. As they were the guardians, and occasionally the cause of Negativity. The Common folk began constantly attacking Nightmares, normally ending in deaths. Eventually, The Corruption that had started at 5% on the nightmares began growing. Due to their hatred towards the Common folk. Eventually, Nightmare snapped and almost killed Nightmare!Chara and Nightmare!Papyrus, from hallucinating, due to being half asleep. when he woke up, he assumed he had killed them. Blaming Dream for all his failures, he attempted to murder Dream, finally reaching 50% Corruption. After Dream escaped, Nightmare fled the AU. After Error manipulated him in his Dreams, he eventually formed a small faction of villains. Eventually he was defeated by Error, and Error took over. Then he allied with him against The Protectors. Turning into a Cold Engine of Destruction.

Personality and Appearance
Nightmare is generally cold and silent. However unlike Error, his clothes are filled with stains. Rather than having a glowing blue eye all the time, his eye is normally pitch black. Sometimes a small white pupil is in it, however it is rare. He normally has something of a slow stumble rather than a walk. He almost always has a Sadistic Smile on his face. His Personality is cold and dark. While he generally doesn't talk much, other than orders, or some sort of speech, he does often make others fearful. Due to his lack of Empathy, he generally not care what he does to you, no matter how cruel or disgusting.

Powers and abilities
Sans abilities - Self Explanitory

Tendrils - He has access to Tendrils that come from his back, which he can use to attack his enemies

Nightmare Blade - He has access to a sword made from Pure Negativity, which he can summon and de-summon at will.

2nd Phase - Upon being damaged to nearly lethal levels, His eye will glow bright red, and initate a much stronger phase.

Goop - He can form his body into whatever shape he wants, assuming he has enough goop. However, he is still vulnerable to physical attacks if you go for his soul directly.

Special Attack - Nightmare will open a Gate between Life and Death, The dead will attempt to drag his enemies down to hell. This attack is always a one-shot, unless the being is 20th Dimensional or Higher, as at that point Nightmare can't comprehend them.

Dream!Sans
He blames Dream for everything bad that happened, so he harbors hatred towards him of extreme levels. To some extent, he's simply reflecting his self loathing onto Dream.

Error!Sans
He works for Error. Despite not exactly liking him very much, he still respects his power and intelligence. He doesn't often attempt to overthrow him simply because he knows it would fail.

Killer!Sans
He's his most trusted minion. However, due to him being extremely paranoid, his trust doesn't even go that far.

Ink!Sans
He generally hates him for no exactly specificed reasons. Other than him leading The Protectors.

Trivia

 * He has a sticky cat named "Furball."
 * He drinks Pure Nightmare fuel rather than Ketchup


 * He can only be uncorrupt by accepting who he is, rather than just not eating a negativity apple.
 * He has a fear of Sunlight, as it burns him