Bird Sans

Birdtail is an alternate universe (AU) where: all monsters have bird-like wings (sometimes tails), the characters' clothing is adapted for flight (often including aviator glasses), the characters' basic character traits are generally preserved, but may be supplemented with new details.

In Birdtail, Sans is represented as a crow.

1. Love of money. Unlike Classic Sans, who is lazy and loves to joke, Bird Sans shows a pronounced interest in material wealth. This may be due to the need to maintain his "nest," purchase flight equipment, or simply reflect his pragmatic nature.
2. Flight adaptation. Like other monsters in this AU, he can fly. His clothing likely includes: lightweight, streamlined elements, protective goggles (to keep the wind out while flying), and possibly some accessories that emphasize his "crow-like" appearance (for example, feathers in his clothing).
3. Interacting with the Environment. In a world where everyone flies, Sans uses his abilities not only for movement but also for: observing others from above, unexpectedly appearing and disappearing (which adds to his mystique), and performing small tasks for a fee.
4. Relationship with Papyrus. His brother, Papyrus, also has wings in this AU (possibly of a different kind). Their dynamic remains: Papyrus is still energetic and dreams of joining the Royal Guard, and Sans teases him but secretly cares for him. Papyrus's clothing is also adapted for flight—for example, he might have special straps or attachments for his wings.
5. Role in the plot. When Frisk (in Birdtail, a small bird with a long tail) enters the Underground, Sans greets her with his usual grin, but now with added "bird-like" features:
   He can land right in front of her with a flutter of wings, joke around while hanging upside down on a branch or ledge, and sometimes offer to give her a ride on his back if Frisk needs to get somewhere quickly (for a small fee, of course).
6. Special abilities. In battle or when interacting with the world, Bird Sans can:
   use bones that fly out from under the wings like projectiles, dodge attacks by sharply soaring upwards or diving downwards, distract the enemy by imitating a bird's cry.

1. Main features:
   Race: Skeleton with bird features.
   Height: short (corresponds to the original Sans).
   Skeletal structure: visible, but partially covered by clothing and feathers.
   Wings: large, black, with soft and delicate tissues - a sensitive area.
   Tail: short, crow-like, with several long feathers.
   Eyes: white glowing (like Classic Sans), pupils can narrow/dilate depending on mood.
   Smile: Sans's signature half-smile, slightly asymmetrical.
2. Clothing and accessories:
   Jacket: fur, black and blue, with a hood and soft fur trim - protects from the wind during flight.
   Jacket: blue, loose, does not restrict the movement of the wings.
   Shorts: black and blue, cropped, comfortable for flying.
   Socks: blue, high, mid-calf.
   Shoes: large soft slippers with imitation bird claws (not sharp, more decorative).
   Glasses: Orange aviator goggles (often worn on the forehead or over the eyes depending on the situation).
   Accessories: Sometimes wears a small leather pouch on his belt for coins or small finds.
3. Details:
   Feathers: Black, shiny, especially noticeable on the wings and tail, may stand out slightly when surprised or irritated.
   Posture: Often relaxed, may sit on a ledge or branch with legs dangling, or hang upside down, clinging to the wings.
   Movement style: lazy, but when necessary - fast and precise, in flight it makes wide, smooth wing beats, can dive sharply or hover in place.
   Sounds: Sometimes makes short crow-like sounds (cawing) instead of words or as a reaction to something.
   Facial expression: usually relaxed and slightly mocking, but can become serious in tense situations.

4. Visual accents:
   The contrast between the skeleton and the bird-like features: bones are visible on the face and hands, but the wings and tail are completely feathered; the combination of casualness and practicality in the clothes: everything is chosen for flying, but looks as if it was put on "in a hurry"; the orange glasses as a bright element of the image - emphasize his individuality and connection with the aviator aesthetic of Birdtail.

Bird Sans retains the key features of Classic Sans, but adds new nuances.
Basic features:

1. Laziness. Prefers to rest on branches or ledges, avoiding unnecessary activity. If they need to go somewhere, they'll rather offer to fly.
2. Irony. He loves to make fun of others, especially his brother Papyrus. His jokes often involve flying, feathers, or bird-related topics.
3. Pragmatism. Unlike the original, he's more interested in money—he might offer help for a fee or negotiate even on small matters.
4. Observation. Often watches events from above, noticing details that others miss.
5. Hidden Kindness. Behind the mask of indifference and cynicism lies a deep concern for those close to him—especially Papyrus and those he trusts.
6. Independence. Values ​​freedom and the ability to go anywhere. Dislikes restrictions and rules.
7. Mild adventurism. Sometimes they give in to the urge to play a little prank or test how far they can take a joke.
   Features of Birdtail:
8. A love of flying. For him, flying isn't just a way to get around, it's a source of pleasure. He might suddenly take to the air just for the sheer joy of it.
9. Bird-like habits. Sometimes involuntarily caws instead of speaking, preens feathers when nervous, or ruffles them to express emotion.
10. Mercantile with humor. His interest in money doesn't come across as greed, but rather as a game or a pretext for yet another joke.
11. Adaptability. Quickly finds a way out of a situation, using wings and cunning instead of brute force.

1. Tone and manner: relaxed, almost sleepy voice, but with a hint of mischief, often speaks with a slight grin, even if the interlocutor does not see it, may deliberately prolong pauses to tease the interlocutor.
2. Typical phrases and speech patterns:
   "Hey, chick, don't get lost" (addressing Frisk or other characters), "To fly or not to fly... Oh well, I'll just fly" (parody of famous quotes), "I could take a coin for that joke... But okay, I'll give it to you" (emphasizing commercialism as a joke), "Is Paps trying to fly vertically again? Someone forgot to spread their wings" (joking at his brother), "I saw something interesting from above... But I'll only tell you if you treat me to a nut" (hint at payment for the information).
3. Methods of interaction:
   With Papyrus: He teases, but always has his back in a critical moment. He can unexpectedly catch his brother mid-flight if he's losing altitude.
   With Frisk: a friendly, mocking tone, willingness to help (for a nominal fee or in exchange for something). May offer an aerial "tour" of the Dungeon.
   With strangers: a cautious, ironic approach. He'll first assess them from above, then decide whether it's worth descending for a conversation.
   In combat: minimal words, maximum action. If he jokes at all, it's short and caustic—for example, he'll say, "You're flapping your wings too slowly" before dodging.
4. Non-verbal signals: winks with a glowing eye (if the glasses are pushed up on the forehead), caws or makes short bird sounds instead of answering, flaps wings to emphasize words, may hang upside down during a conversation to show relaxation or to tease.

1. Name: Bird Sans.
   Appearance: skeleton with features of a raven.
2. Age: 26 years old (retains the original Sans's age).
3. Height: 152 cm (corresponds to Classic Sans - short, compact).
4. Habitat: Winter forest, nest on a high cliff (provides a good view and a quick start for flights).
5. Family: Younger brother - Papyrus (in AU also has bird features, probably an albino crow).
6. Occupation: free observer, sometimes carries out small assignments for a fee (reconnaissance, delivery of messages, escort).

1. Material things: shiny objects (coins, crystals, metal trinkets) - collects them in her nest, nuts and berries from the Winter Forest - considers them "fuel" for flights, warm, soft things - loves to wrap herself in a fur cape after a long flight.
2. Activities and pursuits: flying at high altitudes, soaring in air currents, observing the surroundings from above - feels like an "invisible guardian", jokes and pranks (especially on Papyrus), resting in secluded places - can fall asleep right in flight, smoothly gliding down, "air races" with other flying monsters (the winner receives a prize).
3. Social aspects: spending time with Frisk - appreciates her curiosity and readiness for adventure, teasing Papyrus, but then helping him if he gets into trouble, receiving "payment" for help - even symbolic (a nut, a shiny stone), listening to the sounds of nature - especially the sound of the wind and distant cries of birds.
4. Comfort and Habits: Preening when nervous or thinking about a plan, wearing orange aviator glasses (feels more confident), giving impromptu "excursions" around the Dungeon for those who can't fly.

1. Physical inconveniences: damage to the wings - this sharply reduces its mobility and causes discomfort, dampness and rain - feathers get wet, flight becomes difficult, narrow spaces (tunnels, low caves) - cannot maneuver freely, loud, sharp sounds - disorient it in flight.
2. Social situations: coercion to action - hates when he is forced to do something without "payment" or a good reason, disrespect for bird customs - for example, if someone touches his feathers without permission, arrogance and arrogance - especially if the monster considers himself better than others because of the size of his wings or strength, when they laugh at his commercialism - he perceives this as disrespect.
3. Emotional triggers: threats against Papyrus - instantly brings him out of his state of lazy relaxation, the need to explain obvious things at length - quickly loses patience, situations where he cannot use his wings - makes him feel vulnerable, attempts to limit his freedom - for example, forcing him to live in the city instead of the forest.
4. Everyday irritants: the need to clean feathers after rain or mud, too bright lights at night - interfere with night flight, lack of nuts at the right time - considers this a "fuel crisis".

1. A love of glitter. Like real ravens, he's partial to shiny objects—coins, crystals, metal jewelry. Sometimes he collects them in his "nest."
2. Hidden shyness. He doesn't open his wings to unfamiliar monsters because their resemblance to Dr. Gaster's wings makes him uncomfortable.
3. Friendliness towards people. Unlike the original Sans, he is more open to people and willing to help them, especially if they show respect for avian customs.
4. Residence. Lives with Papyrus in the Winter Forest, in a nest built on a high cliff—it offers a view of the surrounding area and allows for quick takeoff when needed.
5. Barrier "Airflow." There's no Core in Birdtail's world, but there is a Barrier that prevents monsters from reaching the surface. Bird Sans has studied it and knows several weak points—but he doesn't tell anyone about them.
6. Special habits: likes to clean his feathers when he is nervous or thinking about a plan, sometimes falls asleep right in flight, gliding smoothly down, can accidentally croak instead of a word if he gets distracted.
7. Culinary preferences. She loves the nuts and berries that grow in the Winter Forest. She considers them "fuel" for flying.
8. Attitude to heights. He feels more confident and powerful when high up—the higher he flies, the more confident he feels.
9. Secret Hobby: Sometimes he organizes "air races" with other flying monsters, but always sets a condition: the winner gets something valuable (usually a shiny trinket).
10. Symbolism. His image combines the traits of a wise bird and a lazy skeleton, making him simultaneously mysterious and appealing.

1. Raven's wings. Large, black, and sensitive, they allow for long periods of flight, but require careful handling. They can fluff up slightly during strong emotions.
2. Bird-like agility. Excellent coordination in flight: able to change direction abruptly, hover in place, and dive without losing control.
3. Altitude tolerance. It's not afraid of high-altitude flights and can soar for hours on air currents.
4. Enhanced vision. Sees farther and more clearly than normal monsters – notices details from above, aiding in surveillance and reconnaissance.
5. Sound communication. Can produce crow-like sounds (cawing) to convey simple messages or express emotions.

1. Flight: primary mode of movement, can carry a small load (for example, Frisk on its back), and is capable of making long flights without rest thanks to the raven's endurance.
2. Maneuverability in combat: evades attacks by sharply soaring upwards, diving or making turns, uses height as an advantage: attacking from above or retreating to a safe distance.
3. Feather Throw: Throws individual feathers as sharp projectiles - low damage but high attack frequency, feathers can temporarily blind or distract the enemy.
4. Aerial Bone Attacks: Launches bones from a flying position - the trajectory is harder to predict, can create a "rain" effect by releasing many small bones at once.
5. Air Shield: Creates a whirlwind of feathers and wind around itself, blocking some attacks, the shield dissipates after several hits or after a short time.
6. Overhead Surveillance: Patrols the area, spotting threats or points of interest before others, and shares information with allies, indicating targets for attack.
7. Tactical retreat: in case of danger, it instantly takes off, leading the enemy to an inconvenient area (narrow passages, open spaces), it can pretend to “fall”, and then sharply gain altitude and attack from an unexpected angle.
8. Sound tricks: Imitates the calls of other birds to distract, confuse, or call for reinforcements, uses croaking as an alarm or command to allies.
9. Nesting instinct: navigates well in complex spaces (rocks, ruins) - chooses convenient places for rest and ambushes, remembers safe routes and shelters, can lead allies along them.

1. "Crow's Whirlwind" - a fast flight in a circle with a scattering of feathers, creating a curtain and disorienting the enemy.
2. "Shadow Throw" - a sharp dive with the glowing eyes turning off for a split second, which makes the attack invisible.
3. "Exchange of pleasantries" - a humorous but effective technique: throws a pen with a note ("Pay the fare!"), distracting attention before a serious attack.
4. "Brotherly Duet" (with Papyrus) - Papyrus creates a bone trap on the ground, and Bird Sans drives the enemy into it from the air.
   Limitations and weaknesses:
5. Sensitive wings. Damage to feathers or wings reduces maneuverability and flight range.
6. Space dependence. In narrow tunnels or rooms with low ceilings, it loses its mobility advantage.
7. Selfishness. May refuse help without payment if they don't consider the situation critical.
8. Laziness. Sometimes underestimates the threat, putting off action until the last moment.
9. Emotional reaction. When strongly irritated, the cat begins to croak more frequently and loses some concentration.

1. Sensitive wings. Damaged feathers or wing injuries significantly reduce maneuverability and flight range. Recovery requires time and rest.
2. Vulnerability in confined spaces. In narrow tunnels, caves, or rooms with low ceilings, the main advantage – the ability to fly and maneuver freely – is lost.
3. Limited load capacity. It can carry a small load (like Frisk), but when overloaded, it loses speed and maneuverability.
4. Dependence on weather conditions. Strong winds, rain, or thunderstorms make flight difficult and attacks less accurate.

1. Limited supply of attack feathers. If you use "Feather Throw" for too long, your supply will decrease, temporarily unavailable.
2. Energy consumption of special moves. "Crow's Whirlwind" and "Shadow Throw" require a lot of energy—after using them, Sans becomes less mobile for a short time.
3. Weakness to sonic attacks. Sharp, loud sounds disorient him, disrupting his coordination in flight.

1. Laziness. Often underestimates threats and puts off action until the last minute. May ignore danger if it seems "too much trouble."
2. Selfishness. Sometimes refuses to help without "payment," even in critical situations. This can lead to the loss of allies or missed opportunities.
3. Emotional reaction. When strongly irritated, he begins to croak more frequently than usual and loses some of his concentration, making him more vulnerable in combat.
4. A tendency to make jokes at inappropriate times. May become distracted by the idea of ​​another joke, missing an important moment in a battle or dialogue.
5. A hidden affection for his brother. Papyrus is his weak spot. If Papyrus is in danger, Bird Sans can act impulsively and risk his own life.