In this version of underfell, the monsters trapped within Mt. Ebott have been forced to thrive off of hatred instead of kindness. This has warped their bodies and mind into blood thirsty creatures, and its up to the player to decide if they’re worth saving or not.

Flowey-
Flowey(depicted as an ox-eye daisy rather than a buttercup) has survived this harsh world in solitude up until the player’s arrival. He has seen the cruelty of the underground, and would love nothing more than to escape, and condemn every monster to remain in their prison within the barrier forever. Because of this, Flowey is motivated to help you, rather than torment you.

The Player-
A new fallen child has descended upon the underground, and this child’s soul is filled with Hope rather than Determination (so their heart is pink instead of red).
With how corrupted the underground has become, The monsters can only be healed of their hatred with acts of kindness, or exterminated by a cruel power far superior than their own. As the player kills, their hope is replaced with determination (the heart will gradually turn red over time)

Toriel-
Hidden away in the ruins, this Boss monster wishes to forget all about the horrid world that lies beyond the ruins door, and believes the safest place for the player to be, is under her vigilant eye. She refuses to acknowledge how unhappy, and at times rather lonely, she is in the ruins, as even they are starting to crumble and change under the effects of the new state of the underground. She has a “mama bear” type personality in this world, succumbing to her own hatred for how warped the monster population has become, and will crush anyone (or anything) that tries to harm what she loves.

Sans-
This skeleton has given up completely, on ever reaching the surface, on ever repairing the rift between him and his brother that this corruption caused, and on hope. At this point, he just wants to watch the underground burn in it’s own brand of chaos, as these unstable creatures tear themselves, and each other, apart. His humor has taken on more of a banter, and his love for pranks have become a little more harmful to those he plays them on. He doesn’t want to be saved, he doesn’t want to make friends, he just wants things to go back to the way they were…back before…..[redacted]

Papyrus-
Witnessing all of his friends become badasses, he thought he’d join the fray. This skeleton has filed his teeth to sharp points, ditched his old battle body for some stolen plate armor, and has decided to form a gang. He believes if he can show the king the level of authority he has, he’ll surely get into the royal guard then!
He has cranked his edgy behavior all the way up, even more than his peers could even attempt. Papyrus aspires to be the most aggressive, the most intimidating (the most dashing) captain of the royal guard there ever was. Even moreso than Undyne

Undyne-
This former captain of the royal guard fought tooth and nail to the top, only to be forced to do something horrible for her initiation to the royal guard. After being put through much neglect, and mistreatment from the king and the royal guard. Undyne swore vengeance, going full rogue, and vowing to hinder the king in any way she could.

Alphys-
Royal scientist (or should I say engineer?) gone mad with power; her madness further fueled by her fear of disappointing her peers, and of her lies and secrets being exposed. Alphys had worked along side Undyne to reach where she is now, the only difference, is she had used Undyne as a stepping stone to achieve greatness, leaving her friend behind to impress the king. Now filled with regret, she wishes there were some way to make ammends, but with the state the underground is in, it doesn’t seem likely

Mettaton-
The Rockstar robot of the underground. He hopes to lift the monster’s spirits with his amazing guitar and vocal skills. He believes he is the origin of rock ‘n’ roll, and the “devil horns” sign, is an ode to his antennae. He has the personality of a spoiled rockstar, and has wrecked his own hotel on many occasions due to standards not being met.

Asgore-
The king of the underground, and a most miserable one at that. He has accepted what his people have become, and hopes to utilize their hatred to strengthen them, and wage a fair battle on humankind after being imprisoned for so long.
He has lost his wife, his child, and has done horrendous things for the sake of his people. He has dismissed the old prophecy and is determined to make his own fate. Right now the underground doesn’t need old stories, it needs a miracle.