Because he was a god of the dead.
His temper, and his moodiness.
Yes when he is mad
God of the Underworld.
If you angered him. He would place you in Tarturus.
he could choose where you went after you died
All the gods of ancient Greece could be considered dangerous, especially if they were upset or offended in some way. For the most part, though, Hades kept to the Underworld (also referred to as Hades) and left the living alone. The most notable exception was when he stole Persephone to be his wife. He was more inclined to answer curses than prayers so he could be considered dangerous in that sense. The people of Ancient Greece rarely even said his name, although this was likely more from fear of his station than fear of his specific wrath. More than most gods, though, Hades was reguarded as just and fair.
Zeus, Poseidon and Hades divided the world between them, and this is what Hades got.
Hades is Hades' Greek name.
Hades is the Greek name for Hades.
Hades' Greek name is Hades.
Hades the god was in charge of hades the underworld.