Bad Boys

Nightmare as a leader is a cold pragmatist who rules through fear, need, and the vices of others. He doesn't build a team on loyalty: each of his subordinates is held together by the fact that Nightmare provides them with what they need to survive—control for Killer, purpose for Dust, sustenance for Horror, existence for Cross.

He himself remains aloof and calculating: he doesn't waste energy on senseless cruelty, but he also shows no warmth. His "care" for his comrades stems from possessive control, a fear of losing his tools, not affection. Deep down, he's lonely and embittered, and his power rests on his ability to exploit others' weaknesses better than anyone else.
Appearance:
A black skeleton covered in liquid darkness, like tar. One eye is closed/melted, the other glows blue in its dark socket. Four black tentacles protrude from its back. Its clothing (hoodie, shorts) is barely visible—fused with its body. Its height, according to various sources, ranges from ~122 cm to ~188 cm.

Killer Sans, as a subordinate, is a broken tool with remnants of personality, who chose this place because he has nowhere else to go. Nightmare keeps his soul in "stage two"—blunted emotions, obedience, controlled cruelty—to prevent Killer from breaking into uncontrollable rage or, worse, from feeling.

Their bond is one of codependency, built on control: for Nightmare, Killer is a valuable asset and a source of negativity; for Killer, Nightmare is the only available "support," albeit a toxic one. He carries out orders with laziness and sarcasm, but deep down, he is driven by the fear of losing this position and returning to the way he was. His loyalty borders on a lack of self-preservation: he allows his boss to strangle him if he believes it will serve the team.
Appearance:
Looks like regular Sans, but with key differences:

· Chest: A red soul in the shape of a target (symbol of determination/hatred) is always visible in the center of the chest.
Eyes: The eye sockets are usually empty, with a black liquid (similar to mascara or liquid hate) flowing from them. Pupils sometimes appear briefly in the eyes, especially during strong emotions (anger, etc.).
· Clothing: dark blue/gray-blue zippered jacket with cream fur on the hood, black turtleneck, white shorts with black stripes, blue sneakers.

Height is about 185 cm (according to some sources).

As a subordinate, Dust Sans is a quiet, broken tool who follows orders not out of loyalty, but because his psyche is already shattered, and Nightmare provides him with a purpose and victims. After killing his own brother, Papyrus, Dust's sanity collapsed, and he began hallucinating Papyrus, who alternately mocks him and then pushes him to commit further murders.

For Nightmare, he's the perfect subordinate: paranoid, isolated, and driven by a guilt he can't forgive himself for. Their relationship is a cold transaction, not a bond. Dust views his boss more as a beneficial leader than as an authority figure to whom he's emotionally devoted. He doesn't seek approval, doesn't curry favor, and doesn't take initiative without orders—he simply gets the job done quietly and efficiently. Within the gang, he's a silent enforcer: reserved, speaks little and to the point, and isn't aggressive without provocation. Nightmare keeps him close because his broken state feeds his boss negativity, while his skills make him useful.
Appearance:
The main feature: his face is hidden under a hood, but not by fabric, but by an impenetrable black void - his skull is almost invisible.

Eyes: In this darkness, one eye usually glows—a blue pupil with a red rim. During intense emotion, the pupil becomes round and bright, and sometimes a second red eye appears.

Smile: When grinning, sharp teeth and a long purple glowing tongue emerge from the darkness.

Clothing: blue/dark hoodie, dark shorts, heavy boots. Everything is covered in the gray dust of slain monsters.

Height: about 192 cm.

Horror Sans, as a subordinate, is a brute force held together by despair and hunger. His world is dying of energy starvation, his body barely sustained by magic, and his only reliable source of nourishment is the eyes of others. Nightmare provides him with access to food and survival, so Horror cooperates not out of faith in the cause, but because without his boss, his world will die, and he himself will degenerate into a beast.

Their relationship is a parasitism built on desperation: Nightmare uses hunger as leverage and feeds on the negativity Horror constantly exudes. He occupies the position of "heavy force" in the gang—not a tactician or a mage, but one who crushes resistance brutally and bloodily, combining bones and KR with close combat. However, he is no "stupid butcher": he remains a dangerous mage, just with a more feral, hungry aggression. In everyday life, he is silent, sullen, and irritable, and when his magic runs low, he becomes more cruel and unstable. He retains a protective instinct: he still tries to protect Snowdin and his brother, even in a distorted form.
Appearance:
Skull: A large crack/hole in the upper left side of the skull (result of being struck by Undyne's spear). The smile has become wider and more manic, often drooling.

Eyes: The sockets are completely black. The left eye has a glowing blood-red pupil, the right is usually empty.

Clothes: the same as classic Sans, but dirty and bloody: blue jacket with fur trim on the hood, white T-shirt (stained with blood), black shorts with white stripes, blue sneakers.

Body: Bones weakened by years of starvation. Height about 193 cm (6'4").

Weapons: Often depicted with a large axe.

Cross Sans, as a subordinate, is a prisoner of a deal, not a soldier by conviction. After the destruction of his X-Tale universe, Nightmare found him in a moment of despair and offered his help in exchange for his obedience. For Cross, this wasn't a choice, but the only available option: without Nightmare, he would simply cease to exist.

The key to his role is prioritizing survival over freedom. He consciously chooses subordination, even if it means giving up his autonomy, because the alternative is oblivion. Nightmare doesn't trust him and builds relationships not on loyalty but on raw necessity, using the loss of the universe and emotional instability as leverage. Cross isn't a "favorite" like Killer—he's a functional tool whose utility (cracking the code of universes, manipulating gravity) justifies his existence.

Within the gang, he occupies the position of a hacking specialist and tactical fighter, not a brute force. His demeanor is sullen, irritable, and withdrawn: he keeps to himself, doesn't seek company, and doesn't take initiative without orders. His loyalty is one of reluctant compliance, not warmth, and his residual connection to Dream creates an internal conflict that Nightmare likely recognizes and exploits.
Appearance:
The main feature: black and white color scheme and crosses/"X" everywhere possible.

Face and eyes: Before the events of Underverse 0.4, he had one white and one red pupil, and a red lightning-shaped scar under his right eye socket. After 0.4, the scar and red eye disappeared, and both pupils became white.

Clothing: A white hooded jacket (with white fur) over a black shirt, black shorts with white "X"s on the legs, and white sneakers with crosses. He wore a gold heart-shaped medallion and a tattered black and white cape.

Later (after 0.6): the jacket hangs on the hips with tied sleeves, the T-shirt is torn at the shoulders and has a hole in the center, the medallion is attached to one of the blades.

Weapons: Initially, the "Hack Knife"—a large code-breaking knife. Later, twin sabers.

Height: data varies - 184 cm

Dream Sans - Leader of the Star Sans
Dream is the team's inspiring center, whose leadership is built on empathy and an unwavering belief in the best. He doesn't bark orders, but leads by example, remaining the squad's moral compass. His strength lies in his ability to unite diverse characters and remind them of why they fight. His weakness is his excessive softness: he gives enemies too many chances and hesitates when it's time to act harshly. This is precisely why he needs assistants who can compensate for this kindness.

Ink Sans - "Brain" and "Artist"
Dream's right-hand man, responsible for reconnaissance and planning. With paints and a brush, he can literally draw a way out of a hopeless situation—creating a necessary item or portal. Ink is a pragmatist and a skeptic: he often argues with Dream, pointing out the naivety of his plans, but deeply respects him for his steadfastness. Their dialogue is a classic idealist-realist tandem. Ink grumbles that "the plan is suicide," but still draws everything he needs and keeps a Plan B ready.

Swap Sans - "Shield" and "Conscience"
The second assistant, responsible for field work and emotional support. He is incredibly strong physically, but his greatest strength is organization: he oversees supplies, evacuates the wounded, and ensures civilian safety. Swap is Dream's emotional anchor, his fiercest defender, and his most honest critic. If Ink argues with logic, Swap simply says, "Dream, this is a bad idea, and you know it." His openness inspires trust among the locals, making him the link between headquarters and the field.

Final dynamics
Dream provides the purpose and morale ("We fight to give everyone a chance"), Ink provides the method and creativity ("Here's how we'll do it, even if it's impossible"), and Swap provides the execution and care ("I'll make sure everyone survives"). Together, they're not just a squad, but a true family, where the leader inspires, the pragmatist calculates, and the protector protects.

The "Bad Sanses" and the "Star Sanses" are two opposing factions in the multiverse. The Bad Sanses strive for destruction and chaos, denying the value of other worlds. The Star Sanses, led by Dream, protect the innocent and offer even their enemies a chance for redemption. Their conflict is one of destruction and hope: the former see the multiverse as a resource for power, the latter as a home to be protected. This enmity is ideological and defines all their clashes.

Dream's appearance:
The main feature: a golden crown, yellow-blue colors and a “sunny” aesthetic.

Eyes: glow yellow (in some descriptions - turquoise).

Cloth:

· Light blue/turquoise jacket (in the old version) or yellow cloak/cape with a sun design on the back.
· Gold belt with the initials "DS" and bells on the sides.
· Black leggings (later version).
· Golden boots and fingerless gloves.

Weapon: A light blue staff with two golden stars on the ends that turns into a bow.

Height: shorter than classic Sans (about the same as Swap!Sans) 163 cm

Ink's appearance:
The main feature: artistic chaos, a brown palette and eyes that change color and shape.

Eyes: The pupils are never white and change with each blink depending on the emotions (yellow stars - joy, red targets - anger, etc.).

Face: on the right cheek there is an indelible black ink stain.

Cloth:

· Long light brown/beige scarf (often with notes).
· White t-shirt, brown jacket/vest, overalls which he wears as pants.
· On the chest there is a belt with rainbow paint cans (with heart-shaped lids).
· Without shoes (barefoot).

Behind the back: a huge brush (Broomie).

Feature: under clothes on the ribs - strange ink patterns/tattoos.
Height: 176 cm

Swap's appearance:
· Eyes: blue pupils, eyebrows present.
· Build: plump, short.
Clothing: Gray armor with blue details, blue cloak/scarf, white shirt, dark blue pants, blue boots. No gloves.
Height: 165 cm