Herobaal

Known only as one of the Agents of Gruumish, the god of orcs and destruction, Herobaal is a feared by all and has no sympathy for the damned souls that wander the halls of his stronghold in the Plane of Fire. He has a weakness for power and resembles a gargantuan pit fiend. He is worshiped by cults as the "Lord of Souls", collecting the cursed and evil souls that find themselves in the Plane of Fire.

Worship
Many demonic cults worship him, as well as many inhabitants in the Nine Hells. Most ways of worship involve trapping living sacrifices in one of the Nine Hells but some just go about sacrificing the way that most do. Statues of Herobaal mostly depict him as a large, humanoid with pointed ears, horns, and fangs. Herobaal is feared more than he is worshiped.

Summoning
It is unknown how one is to summon Herobaal, though many have tried. It is a common joke among older children to pretend to summon the lord of souls as a way of scaring their friends. Only one person was ever recorded to have ever summoned Herobaal, but he was only saw the monster for a mere second before it retreated back into the Nine Hells. The summoner then died days later from an unknown cause.

Communication
Although it is unknown how one is to summon Herobaal, it is rather simple to communicate with the demon. You must take the corpse of any humanoid and place a knife in it's chest. Then, you must create a circle of bones around the corpse. Eventually, Herobaal will contact you through the corpse. Be wary; It isn't impossible for Herobaal to use his infernal powers against you while communicating through a corpse.

Rise to Power
Herobaal was created when the amount of souls being kept in the Nine Hells grew too large for the demons to control. The lord of souls actually began as just a pit fiend who rose to the challenge of keeping the souls in line. Over the years, more and more souls have been banished to the Nine Hells, causing Herobaal to gain more and more power until he initially became a demon lord.

Fall from Power
Eventually, all the power that Herobaal had went to his head as he began to deal with mortals. Not being an actual demon lord, this caused a lot of uproar in the overworld AND the Nine Hells. It all began when he decided to possess a tyrant who was the king of Elendul in Vestya at the time. After much toil and the death of the tyrant, three heroes traveled to the Nine Hells and slayed Herobaal. However, one of the heroes was killed in action during the fight. The three heroes were named Krillin, Adran Sianodel, and Mur Belkum.

Trivia

 * Some say that Herobaal still roams the Nine Hells as a pit fiend but it has not yet been confirmed.