In Greek mythology, Hades was not such a monster.
Hades, the god of death and the underworld, is associated with darkness and evil since he is frequently seen as the ancient Greek equivalent of the Christian devil. However, it was not Hades who elected to rule over the underworld. To choose who would rule which kingdom, he and his brothers, Zeus and Poseidon, pulled straws. So, let's just say Hades was unlucky and was sent to the underworld, whilst his brothers, Zeus and Poseidon, were given dominion over the Gods and the sea, respectively. We must remember that, contrary to popular belief, Hades was not the one accountable for either the condemnation or the salvation.