Board Thread:Wiki Discussion/@comment-44601210-20191206012456/@comment-34368001-20191221213647

It's commonly believed that the Red Soul is determination and that actually fits in well with the motif you're describing. Because it was determination that drove Frisk/Chara to accomplish their goals whether they be good or bad. Basically, it's established that determination can go both ways. And while you can do whatever you want in the neutral routes, in the True Pacifist and Genocide routes (the two main and arguably only canon routes of the game) it was Frisk's determination in the former that allowed them to take attacks from a God of hyperdeath and refuse to die while fighting them and allowed them to use their Save ability to save their friends and make peace between humans and monsters. While in the latter, it was Frisk's determination that empowered and brought Chara back to life, and with their determination, they were able to kill all of the monsters and destroy the world of the game. I think determination can go both ways and really ties into the morality themes of the game. With the red soul, the human, it's up to you to decide what you do with their determination.