ハデス (Underworld) is a concept from ancient Greek mythology, representing the realm of the dead. It is ruled by ハデス, the god of the underworld, who oversees the souls of the deceased. The Underworld is often depicted as a dark and gloomy place, where souls are judged and sent to different areas based on their deeds in life. In addition to ハデス, the Underworld includes various regions such as エリシオン (Elysium), a paradise for the virtuous, and タルタロス (Tartarus), a deep abyss for the wicked. The Underworld is also home to mythical creatures like ケルベロス (Cerberus), the three-headed dog that guards its gates.