Underfrail

Frisk: A young homeless child who decides to commit suicide after not being able to support self any longer because parents starved. Chaotic Good.
Chara: A young homeless child who decides to commit suicide after not being able to support self any longer, taken in by the rulers of the underground. Later became sick due to a cyanide pill dissolving in his glass of water (Murdered by W.D. Gaster). Comes back for revenge on all monsters. Chaotic Evil.
Sans: Alcoholic and smoker skeleton who's lives in the underground with his brother. His father, Gaster died and he's become depressed and given up, for the most part, only waiting to starve to death in the slum. Fills ketchup bottles with booze so Papyrus doesn't know he's drinking. Chaotic Neutral. He vows to protect Frisk, knowing what it's like to lose a parent.
Papyrus: Anxious and a hard working skeleton who's trying to find and kill another human so he can afford to buy food and other needs for Sans and him. Tries to keep the family together and stop Sans from drinking. Chaotic Neutral. (Will go apeshit on you if you give a good reason).
Undyne: A fish-monster mercenary working for Asgore trying to kill every human, a previous one having killed her mother as well as earn enough money to live. Chaotic Neutral.
Alphys: A wanna-be scientist who studies ways to break the barrier and more efficient ways of farming and tools but is turned down by Asgore because he doesn't believe that there are possibly other methods of breaking the barrier. Lawful Good.
Napstablook: Anxious, street performing ghost who sings and plays guitar for the money to live. True Neutral.
Mettaton: Cousin of Napstablook and ghost possessing a bot that Alphys created in order to win Asgore over. It was a failure and Alphys became upset and left him in an ally. Because of his handsome appearance he became a model but was depressed because he wasn't useful as originally intended. Wishes to find Napstablook but Napstablook always runs from him, jealous of his fame.
Flowey: A quiet and observant sunflower with 89 petals. Each time Frisk/Chara dies a petal is lost and once the petal count reaches 0 the player must face photoshop Flowey and survive. If they do, the game is completely reset and you start from square one. If you die, you become part of Flower and watch the underground suffer. Neutral Evil.
Asriel: Toriel and Asgores son who had a hatred towards humans due to their history, always arguing with his parents because of their opposite opinion. He found Chara and attempted to kill him until he saw Chara crying and felt pity, and didn't truly feel bonded with Chara until shortly before he died.
Asgore: Former king (Before the government collapsed) of the Underground. Grew a hatred towards humans due to the death of Asriel, forgetting the sweet child Chara was when he was alive. He killed any human who entered the underground, the government and economy falling apart because he chose to put all his attention towards human genocide. His opinion changes once he realizes how Frisk isn't hurting anyone.
Toriel: Former Queen of the Underground and current Theif living alone in the ruins. She vows to keep each human who falls down and kill them if they disobey her (She got a bit fucked in the head after her child died, understandably) and robs the people of Snowdin periodically to survive. She changes her ways when she's about to kill Frisk and Frisk cries, calling her, "Mom."