Killian Jones is the architect of his own hell.
He had died a hero and the ferryman had taken him to the fields of Elysium - endless green hills, a cloudless blue sky and a river as wide as an ocean. He could have been at peace in the afterlife. Liam would have been there and perhaps even Bae.
But the funny thing about hell is that you get what you think you truly deserve.
Arrogant blackguards like Killian's former king might have thought they deserved a palace in the afterlife with riches they could not even spend but deep down, they knew they should burn for all eternity and for all eternity, they did. Hardworking peasants who lived a good life, who raised their children well and provided them with everything their hands and hearts could give, found they wanted no more in the afterlife. And heroes who were men and women of honor and died a clean death found contentment in the welcoming arms of Elysium - a fate they well deserved and knew they deserved.
But Killian Jones did not die a clean death. He had committed many sins - treason, murder, patricide - in his three hundred years as a man and he had almost betrayed his love by sending her family to the depths of hell. He may have died a hero but he felt undeserving of his fate. He could not find any enjoyment in the field of Middlemist flowers, he felt no warmth from the sun, he only felt the turbulence of his own mind and heart when he looked at the waves crashing against the Isle of the Blessed. He spiraled down into the depths of his own self-hatred, all the way to the very bottom of the sea.
His brother, his former lover and even his father called to him, tried to reach him in the depths of his despair. Even Hades frowned down at the lone figure. But Killian could not hear them, couldn't even respond to Hades' prodding, because he could not forgive himself. This forlorn dark empty existence was his just penance for a unworthy life.
Hades had shaken his head at his wife. As the keeper of the dead, he could make exceptions, but even he could not break through the complex maze that made up a man's mind and he certainly could not change a man's heart. "There is no hope," he tells his wife.
But his wife responds with that mysterious serene smile of hers and he sees the goddess of spring in the dark. "There is always hope."
It takes someone extraordinary, a fighter, a savior, a woman in love. It takes a love so True its light even reaches the very depths of a man's personal hell. Death even stepped back to bow at its light. "I haven't seen a love like this in a thousand years," Hades admits and Persephone sheds a tear of joy for the hero and his lady love before letting them go.
They share one heart now. Killian Jones would no more design a lone grey cell of self-loathing but would return to earth hand-in-hand with his True Love and together, they would build their lives, their home and their family.
(Well, he did have to fix the picket fence himself when he crashed her Bug into it in his panic to get to the hospital. It was worth it to hold his first born in his arms. And when he did it again when his second child was on the way.)