Killer Sans

1. Multiple deaths and reboots. Initially, Killer Sans was just an ordinary Sans in his universe. The player would repeatedly complete the GENOCIDE path, kill Sans, and restart the game. By the 176th GENOCIDE, Sans was already aware of all the previous cycles—he remembered everything that happened before the resets.
2. Chara's Proposal. Before his next death, Chara invited Sans to join the GENOCIDE path—to try killing for himself and "enjoy" the thrill, since the game could always be restarted. Sans initially refused, but after another reset, he reluctantly agreed.
3. The beginning of the GENOCIDE. Sans began killing:
   Flowey was the first to be killed, eliminating the possibility of a happy ending. Then Sans killed Grillby: he attacked him in a bar, doused him with water, finished him off with gaster blasters, and burned the place down. The third was his brother, Papyrus. This kill was the hardest for Sans. Before he disappeared, Papyrus said, "If my death makes you happier, then so be it."
4. Chara's Influence and Transformation. Chara encouraged Sans, reminding him that everything would "reset" and that he shouldn't worry. However, Sans felt intense remorse. Gradually, his condition worsened: a black liquid (negative/ink) began leaking from his eye sockets, covering his face. Chara said that Sans's soul would become like his own—devoid of feelings. Then Chara left Sans alone among the flowers.
5. The Birth of Killer Sans. At this moment, Sans's soul changed: it turned red, filled with DETERMINATION, and lost the ability to feel. Thus, Killer Sans was born.

Outwardly similar to Classic Sans, but has a number of distinctive features associated with his transformation after joining the genocide.
Species: Skeleton monster.
Cloth.

1. Jacket - has a grayer shade than Classic Sans's. The hood has cream-colored fur. In some versions, the hoodie can be pale blue to a classic color, with ruffled brown fur around the hood. The bottom of the hoodie has a darker blue trim, and the hood itself is also dark blue on the left side. Sometimes the hoodie has a black spot, which may symbolize "liquid hate" or another characteristic of the character. Under the jacket, he wears a black turtleneck.
2. Shorts - White with black stripes, unlike Classic Sans' classic black and white.
3. Shoes - Instead of slippers, Killer Sans wears sneakers the same color as his hoodie, with a black line at the base separating the blue part of the shoe from the white front. The back of the sneakers has two lines: the top is black, the bottom is white.
4. Soul - The character has a red circle in his chest, symbolizing his soul. Some interpretations suggest this is Sans's own soul, mixed with Chara's.
5. Eyes - A black liquid (ink/symbol of negativity) flows from the eye sockets, which Killer Sans can manipulate. In certain situations, such as when the character experiences strong emotions (such as anger), barely noticeable pupils become visible in the eye sockets.
6. Additional details: Killer Sans is sometimes mentioned to carry a knife, which he uses as his primary attack.
   Killer Sans's appearance and soul can change depending on the stage of his transformation or emotional state. For example, a tiny spot sometimes appears in his right eye socket—a manifestation of Sans's classic personality, attempting to escape during emotional breakdowns.

Killer Sans's personality is the result of his transformation after accepting Chara's deal and participating in the genocide. It combines remnants of Sans's former nature with new traits arising from his warped soul and loss of feelings.
Main personality traits:

1. Ruthlessness and cold-bloodedness. Killer Sans acts calculatingly and without remorse. He no longer feels compassion and sees killing as routine.
2. Lack of empathy. After the transformation, his soul became "devoid of feelings"—he has no empathy for his victims and feels no guilt for his actions (although memories sometimes surface).
3. Sadism and dark pleasure. The character derives pleasure from pain—both their own and that of others. They revel in the chaos and suffering of others.
4. Cynicism and pessimism. Killer Sans sees the world through bleak tones. His worldview is shaped by endless cycles of death and restarts, where any attempts to change the situation seem futile.
5. Multiple personality disorder. In it, two entities coexist:
   Killer is the dominant, cruel and calculating part, Classic Sans is the suppressed part, which sometimes breaks out during moments of emotional breakdowns (for example, it manifests itself as a small spot in the right eye socket).
6. Stubbornness and determination. He is extremely persistent in achieving his goals and is ready to see them through to the end, using all available means.
7. Paranoid traits. Killer Sans distrusts those around him, expecting betrayal or attack.
8. Guilt (repressed). Memories of Papyrus and other victims sometimes surface, causing internal conflicts. He may experience hallucinations or shadows of the past (for example, the image of Papyrus).

Killer Sans's communication style reflects his personality and changes depending on his stage of transformation:

1. Tone of speech: most often cold, detached, monotonous, sometimes mocking, with hints of black humor, in moments of breakdown - emotional, incoherent, with glimpses of the former personality.
2. Characteristic features of dialogue: brevity and directness: he does not like long discussions, sarcasm and ridicule towards opponents, lack of politeness: he can interrupt, ignore or openly demonstrate contempt, use threats and intimidation as a tool of pressure.
3. Speech characteristics: minimal emotion in intonation (when the Killer part dominates), interspersed with Sans's old jokes, but in a distorted, gloomy form, sharp transitions from calm to aggression, in moments of classic personality manifestation - a more lively and emotional tone, apologies or regrets are possible.
4. Reaction to provocations: reacts to insults or attempts at humiliation with a burst of rage; when Papyrus or past events are mentioned, he may momentarily lose his composure.

1. Stage 1 (calm): communicates almost like Classic Sans, but with cold notes, maintains sarcasm, but without aggression, is capable of conducting a constructive dialogue.
2. Stage 2 (classic Killer): speech becomes harsh and abrupt, there are many threats and ridicule, there is no compromise.
3. Stage 3 (insane): speech is incoherent, chaotic, shouting is possible, loses the ability to communicate logically, focuses only on destroying the target.
4. Stage 4 (dangerous): hardly speaks - acts silently and mercilessly; if he speaks, it is briefly and threateningly.

1. Origin: AU version of Sans from a universe where the Player has gone through the path of genocide multiple times.
2. The key moment of transformation: on the 176th cycle of GENOCIDE, Chara invited Sans to join the killing. After much hesitation, Sans agreed.
3. First kill: Flowey (eliminated the possibility of a good ending).
4. Tragic moment: the murder of Papyrus, who before disappearing said: "If my death makes you happier, then so be it."
5. Final Transformation: After a series of murders, Sans's soul turned red, filled with determination and lost the ability to feel - this is how Killer Sans was born.

1. Real knife:
   Deals 99 damage (like in the original Undertale), can cut through almost any physical object, but is ineffective against metaphysical, paraphysical, and immortal entities.
2. Sharp Bones: A stronger version of Sans' standard attacks, the bones are sharper and stronger than usual, deal increased damage, and can control the direction and density of attacks.
3. Killer Blaster: A modified version of the Gaster Blaster, larger and more powerful than the regular blaster, it fires black beams of destructive energy, one of the most powerful offensive abilities.
4. Dark Energy Projection: Releases destructive beams or blasts of dark energy, capable of destabilizing opponents and disrupting their abilities, the radius of damage and strength depend on Killer Sans' emotional state.
5. Knives of Hatred: Normal knives infused with black liquid (symbol of hatred) that absorb the victim's life force, LV, or energy upon impact.

6. Soul of HATE + DETERMINATION: A transformed soul that combines DETERMINATION and HATE increases strength, speed, endurance and durability, and provides high regeneration, allowing one to recover from serious damage.
7. Soul Corruption: Infects the souls of opponents with dark energy through touch, causing the gradual destruction of the victim's essence, weakening the opponent over time.
8. Save and Load: The ability to "save" and "load" after death allows you to instantly return to life after death.
9. RESET: resets the timeline to a certain point, restores the state of the characters and the environment.
10. Timeline Erasure: The ability to erase entire timelines with a snap of the fingers, requires a significant expenditure of energy, acquired through training with Nightmare and joining Team Void.
11. Timeline Distortion: brings chaos and destruction to the course of events in alternate realities, allowing one to influence the development of events in other AUs.

12. Void Cloak: Envelops Killer Sans in a field of partial intangibility, making it difficult for enemies to detect and target, and increasing evasion and stealth.
13. Body Control: Control over one's own physical form thanks to the power of the soul of HATE, flexibility and adaptability in combat (for example, dodging, changing the shape of bones).
14. Control of black liquid: controls the substance flowing from the eye sockets, using it as a weapon (strikes, traps) or a control tool (restricting the enemy's movements).

Stage Dependency: The strength and nature of the abilities change depending on Killer Sans's current state:
Stage 1 (calm) - minimal manifestations, restrained attacks.
Stage 2 (classic) - full access to most abilities.
Stage 3 (crazy) - uncontrollable power, chaotic attacks.
Stage 4 (dangerous) - maximum destructive force, almost unlimited.
Nightmare's Influence: Some abilities (such as erasing timelines) are strengthened or stabilized thanks to Nightmare's mentorship.

1. Transformed Soul:
   shape - a red circle with a target in the center,
   combines DETERMINATION and HATE, the source of supernatural abilities.
2. Black liquid: flows from the eye sockets, symbolizes hatred, can be controlled: can serve as a weapon or a means of control, becomes thicker and more aggressive as abilities are strengthened.
3. Four stages of the state:
   Stage 1 (calm) - retains the features of classic Sans, capable of dialogue.
   Stage 2 (classic) - Killer personality dominates, dangerous and unpredictable.
   Stage 3 (crazy) - loses control, attacks everything around.
   Stage 4 (dangerous) - extremely destructive phase, barely speaks, acts mercilessly.
4. Multiple Personality Disorder: A small spot sometimes appears in the right eye socket - a manifestation of Sans's classic personality; during emotional breakdowns, memories and feelings of the old Sans break through.
5. Hallucinations: he sees shadows of the past, most often the image of Papyrus, these visions can destabilize his condition.
6. Dependence on external forces: Partially controlled by Nightmare, who regulates his state and supports him in the second stage, Chara's influence in the early stages of transformation determined his path.
7. Skeletal physiology with metaphysical changes: retains the anatomy of the skeleton, but with abnormal features (black liquid, red soul), does not experience physical needs (food, sleep), but is prone to emotional breakdowns.

1. Memories of Papyrus: Mentioning his brother or seeing his shadow causes an emotional breakdown, which can lead to a loss of control and a transition to unstable stages.
2. Manifestations of the classic personality: attempts by the old Sans to “break through” weaken Killer; at such moments, he becomes less aggressive and more vulnerable.
3. Knife Limitations: "True Knife" deals 99 damage, but is useless against metaphysical, paraphysical, and immortal entities, requiring recharging or special conditions to use again.
4. Dependence on Nightmare: Nightmare controls his state and can "reboot" the soul, temporarily weakening Killer; without Nightmare's support, Killer can fall into an uncontrollable rage or, conversely, get stuck in a breakdown stage.
5. Guilt: Suppressed, but periodically breaks out through hallucinations and emotional outbursts, destabilizing his resolve and reducing his effectiveness in combat.
6. Energy-consuming abilities: powerful attacks (for example, erasing the timeline) require a significant expenditure of energy, after using them, Killer is temporarily weakened and becomes vulnerable.
7. Vulnerability to "healers":
   influences: attempts to restore his soul (for example, from Color Sans) can cause internal conflict and loss of control, the influence of positive emotions (hope, kindness) disorients him.
8. Limited rationality in higher stages: in the 3rd and 4th stages, he loses the ability to think strategically and acts chaotically, which makes him predictable for experienced opponents who know how to provoke the transition to these phases.
9. Susceptibility to manipulation: opponents who know his past and weaknesses can use this for psychological pressure (for example, by reminding him of Papyrus or his previous jokes).

1. Chaos and destruction - enjoys general instability, quarrels and conflicts.
2. A sense of power and control - enjoys being able to dictate terms and subjugate others to his will.
3. Dark humor - appreciates dark jokes, especially those that make others uncomfortable.
4. Moments of manifestation of the former personality - subconsciously values ​​rare flashes of memories of himself before the transformation (but tries to hide it).
5. His strength and abilities - he is proud of his new abilities, especially the ability to manipulate time and erase timelines.
6. Black liquid - considers it a symbol of his new essence, uses it as a weapon and an instrument of control.
7. Battles with strong opponents - experiences excitement when faced with a worthy opponent.
8. Lack of restrictions - values ​​the freedom to act without moral boundaries and rules.
9. Sense of Superiority - He enjoys knowing that he is stronger than most beings in the multiverse.
10. Nightmare as a mentor - respects him for his strength and support, although he does not always agree with his methods.

1. Reminders of Papyrus - any mention of his brother evokes painful memories and can trigger an emotional breakdown.
2. Weakness and compassion - considers these qualities to be signs of vulnerability, despises them in others and in himself (when they manifest themselves).
3. Attempts to "fix" his soul - reacts with hostility to attempts by Color Sans or other characters to return his former feelings.
4. Charu (in most versions of the story) - hates him for the deal that led to his transformation and for his manipulation.
5. Optimism and hope - the ideas of Dream and other positive characters irritate and make him aggressive.
6. Limitations of his abilities - gets angry when his powers don't work (for example, a knife is useless against metaphysical entities).
7. Hallucinations and visions of the past - the shadows of Papyrus and other victims prevent him from concentrating and destabilize his condition.
8. Loss of Control - Hates moments when his personality fluctuates between Killer and Classic Sans.
9. Ink Sansa and his ideals - despises Ink for promoting creativity, hope and goodness, considers him naive and irritating.
10. His own sense of guilt suppresses him, but it periodically breaks out, causing internal conflict and weakness.

His own sense of guilt suppresses him, but it periodically breaks out, causing internal conflict and weakness.