I do admire however the symbolism that is presented with Doyle's death. Because he is half demon one could argue that in his death he was saving the humanity of all that would die before him. Doyle transforms into his demon form when he jumps into the "Beacon of Light" and deactivates it however in doing so it kills him. As he dies he transforms back into a human as his demon side withers away before the light and though it kills him, Doyle does so with a human smile. This death symbolizes the cleansing of Doyle's past inaction and purification to redeem himself as he dies in his human form, thus saving the rest of the half demons.
Even though the death of Doyle causes me a bit saddened it happened in a way that is fitting of any person who is trying to make right things that they may not have been able to in the past, granted I'm not saying everyone should die to save the masses just to right a wrong but that it is "never too late" to change the way your life is led.