Hades
Hades is a prominent figure in Greek mythology and has been featured heavily throughout literature. He was the god of the underworld and ruler of the dead, which made him one of the most powerful gods in the ancient Greek religion. His presence can be found in various works, ranging from Homer's Odyssey to Virgil's Aeneid, as well as later pieces such as Dante Alighieri's Divine Comedy. In these stories, he is often portrayed as an ominous character who will do whatever it takes to protect his domain.
In Homer's Odyssey, Odysseus encounters many challenges on his journey home from Troy, including a stop at Hades' kingdom, where he must consult with Tiresias for advice about how to complete his mission. This passage paints a vivid image of what life would have been like for those unfortunate enough to enter this realm: "We went down into dank Tartarus. and there were gates wide open before us; but so far forward no man might go/ For chill blasts blew out of them that made us shrink aback." It also shows just how intimidating Hades can be when someone encroaches upon his territory uninvited: "At once up rose dread King Aeaean hailing us with a terrible voice." Despite being feared by all mortals, Hades had respect for certain heroes and granted favors to some if they earned them (as seen when Heracles comes looking for Cerberus).
The portrayal of Hades has evolved over time, mainly thanks to its association with Christianity, which shifted public opinion from viewing him solely as an evil entity towards seeing him more sympathetically, especially since Jesus himself spent three days in Hell after dying on the cross, according to the scriptures. As such, modern interpretations tend to depict a much softer side than what we find in classical texts while still maintaining aspects like deep secrets or hidden knowledge attributed traditionally to this deity.