Wartale — A Russian Undertale AU.
Toriel had lost her only son, Asriel, and much has changed since then. They have became cruel and merciles. The hatred felt after Asriel's death drove her to wanting the destruction of humanity for the sake of monsters. Due to Dreemurr's (Asriel, I think) coup, a civil war broke out. Some monsters have moved to thier side (Sans, Gaster, Muffet, etc.), Others just want the world to be at peace remained on the side of Asgore (Undyne Alphys, Papyrus, and others.)
Toriel's party conducted experiments on 6 fallen men and monsters, and stole their souls (as well as subjected to physical torture). Basically, it is because of these factors, the supporters of extermination began to despise and hate them.
Because of the war many of the monsters are enemies of each other. For example, Sans and Papyrus are feuding among themselves, as the shorter skeleton sided Toriel and experimented on the monsters and humans, while his brother only wanted peace. Later Sans regretted his choice, but he could not change it for it may lead to more disasters.
Frisk is afraid of Gaster and the monsters who want to kill her, as well as fearing the experiments, but friendly to Sans and Papyrus.
Gaster is the father/creator of the skeletons brothers, Napstablook and Mettaton and creating them from their ribs and to cross human DNA with theirs.
He is 30 years old. He has a fairly mild nature. Despite being created as a combat robot, he does not like to fight and prefers to help Alphys with their treatment. Since the beginning of the Civil War, Alphys stopped being a scientist and became a doctor to help the victims of the terrorist. Mettaton prefers to be her assiatant. Mettaton has a radio station, where anonymous callers talk about the problems in their life, and he tries to give them good advice and solve the problem. Because of his appearance, pleasant voice and useful tips, he and his show are popular among women, although he is asexual. He has a brother - Napstablook.
When Alphys was assistant to WD Gaster in scientific projects to create artificial life, Gaster already had children, grown from his false ribs. These children were Mettabluki and Napstablook. They were very similar to normal human children, but their skin was very pale, and the white of the eye were black like their father's. The flesh was human DNA for the most part, and the skeleton was monster DNA. They did not survive and the flesh started to rot, Napstablook and Mettabluki died at the age of 13. The second pair of children were Sans and Papyrus, but Gaster decided not to do them at the same time and made Sans to check whether the rot would effect the body parts separately. Sans and Papyrus do have flesh but they are separate from their skeletal forms. Food consumed by the skeleton is teleported to the flesh version inside of their body. This process on works when eating something, forcing something into another orifice will not cause it to teleport. They can chose to wear the flesh whenever they desire but cannot maintain that form for more than a month or the flesh will begin to rot and poison their skeleton.
So, back to Napstablook and Mettaton. Alphys left the business and started to work separately, and soul Napstablook and Mettabluki began to live their lives, but Mettabluki was not very pleased with the idea of living as a spirit. They asked Alfis give him and his brother bodies. Mettaton was created. Since spirits do not have sex, Mettaton appearance was created as a man. He is very sincere and gentle. So when Alphys gave Mettaton a body, he went to Napstablook persuade him to take up Alphys's offer of a body. Napstablook refused, he had wanted to live forever with Mettaton with nothing ever changing and Mettaton gaining a body had ruined everything.
Mettaton usually fights melee, using a combat knife, their equipment is rarely used because it is quickly discharges, this is a severe disadvantage. The soul is in the thoracic region, and is well protected. On the back of his head is a cord which is connected directly to the soul. This allows him to feel and move. He admires Papyrus's strength, kindness and respects him. He hates Sans.
Aged 21. A lover of anime. She sometimes suddenly attacks Papyrus from behind, hoping to surprise him and win. Doing so would see her take the place of the "Chief of the Guard," which Papyrus took from her by winning a duel.
Since she is something like a Nagi, she does not have breasts, so she often wears clothing that gives the bulge in the chest area. She has great physical strength like her canon depiction.
A 28 year old single woman. Since the beginning of the war she had to leave the profession of a scientist and becomes the chief doctor, as there was a shortage of qualified physicians. She smokes and plays video games. This is how she relaxes. By nature she is quiet. She has a crush on Undyne.
When creating Mettaton, she rested against the image of the game characters from the fighting game (Mettaton did not appreciate this).
She can blend into the environment, she is like a chameleon. When experiencing strong emotions, she changes color. Alphys is quite strict, though she always acts very calm.
12 years old and a cannibal. She was a 'waif', a child who lives in the slums, where hunger is rampant. As a result, she became wild and a local killer, murdering and devouring other monsters. She raised one huge spider, and a bunch of smaller spiderlings.
She lived in Toriel's territory, and Muffet's frequent murders causes Toriel to order her capture. Finding a common language with Muffet was difficult, but she has found. Toriel decided to keep the cannibal alive, she was ordered to kill any prisoners sentenced to death.
Muffet barely talks and hardly understand speech, she is like a wild animal. She dislikes lit space and tries to hide in the dark corners
He is always dissatisfied with everything. Alphys created his body during a severe staff shortage, with the beginning of the war and all the doctors falling down. Manpower is still needed, however, so Alphys used the first experimental body for Metatton. He envies Metatton, which is contrary to how Metatton's feelings on his form.
Differences with the canon
Toriel and Asgore have black hair, as well as Asgore having slightly modified features.
Sans's cyan light is replaced with a green glow. In the battle with the papyrus, he loses his right hand, but then replaces it with a creature. Also he has a 1 HP because of "bleeding".
Papyrus can create armor for himself. Has the ability to "bleed" - dealing a heavy blow to the enemy (eg, cuts off a limb), the HP is lowered and rests on a number Papyrus decides. He has a scar on his head (skull splits in to two) in which a surgical saw is stuck. Later Alphys sewed his skull, but could not get the saw.
Flowey has three stems, and three personalities (each stem = an individual), as well as a me-nots.