Hades, who never learned how to love.
...
You have to understand where he's coming from.
Hades blindly followed Zeus for the promise of happiness and freedom, only to be dealt the short straw and landed in the realm of the Underworld, surrounded by death and barren darkness and things that go bump in the night.
Hades, imprisoned by his father, overlooked by his mother and deceived by his brother was freed from the belly of Cronus but trapped in the abyss of the Underworld, betrayed by his own family. Often portrayed as an evil overlord flanked by soulless skeletons, Hades was hated and feared, but most often forgotten.
So you'd think, where would he have learned to love?
He's constantly warring with his siblings. He murders who he dislikes. It's highly doubtful he pays Charon and Cerberus obviously doesn't talk a lot. So the plain answer is no, he doesn't know how to love.
But that doesn't stop him, does it?
