Horrortale Undyne is such a tragic figure to me.
She has rage festering within her, she wants a war with the humans as she sees every fault in them, sees the very reason why monsters are stuck and suffering. But her SOUL hurts for monsterkind, whom she loves and cares for so much, she just wants to see them free, wants their suffering to end already.
She has rage and grief burning inside of her, and it lashes out and its flames will burn anything it touches. She wants to free the very people, who in their desperation broke her mind. But she's the Empress and she has the control and she has the power, no one can ever tell her what to do.
Grief drowns her, she's lost her king, she's lost her love, her hands have hurt friends she cared for deeply. But they're all weak, they're all in the way, if they just obeyed and gave her what she wanted, what she needed, they'd be all free.
The throne she sits on is crumbling, the crown she wears heavy with sin. She talks to portraits of people long gone, asking, begging, for answers and advice that won't ever come. She's all alone and she's angry, she's grieving, if only Sans had not made it so difficult, if only she could've trusted him, if only she had killed that human child. Had they not been friends?