Appius is an apprentice of Pelor from back when he was one of the Magicians. Pelor left him behind on Aand in secret to act as a deterrent in case the other gods tried to exert control over the world. Pelor left him on Hidentia with his original mount, a giant Couatl that can only be awakened if the world is thrown into a certain amount of turmoil. Once this level of chaos is achieved, a Neutral Good mortal would have to go to the Couatl and end it's slumber. Then the mount could be used to stop whatever danger is befalling the world.
Appius was original extremely excited to be given this mission. For one thing, it meant he could stay on Aand while the other Magicians and their apprentices were forced to ascend to different planes. He also took it to mean that Pelor trusted him above all others. He waited patiently, using magic to keep an eye on the world and ensure that nothing too terrible happened that it would be required for the mount to be woken.
When the Isle Empire seemed to be gaining enough power to threaten the gods, Appius grew secretly excited that this meant he could finally serve his purpose. But then the gods made an agreement to handle it on their own and the drow were cursed with sunlight sensitivity which ended their supremacy.
Appius was confused and a little enraged that Pelor joined this agreement when he knew Appius was down here to handle that exact kind of thing. He rationalized it at first as Pelor didn't want to show his hand too early but after a couple centuries of dwelling on this, his paranoia got the better of him and he began to think Pelor had abandoned him. In his anger, he created the Enchanting Storm and sent it across the world, hoping the addition of magic would cause more turmoil and his purpose could be fulfilled. However, with everyone having magic, the world reached equilibrium pretty quickly and the gods all assumed one of the other ones did this and it worked out so they made no efforts to correct it.
Appius was livid with their indifference and his psyche began to crumble. He created a city in Hidentia and stretched his magical limits to create a race of people in the city like the gods did once upon a time. Due to his lower power level, the people weren't as advanced as the rest of the people on Aand. They struggled to understand intangible concepts and couldn't form organized civilization after a century of forced evolution even though they were given a ready made structure for it. This made Appius even more angry and he went on a rampage, destroying parts of the city and killing everyone in it. He began intense amounts of research to find a way to show the gods he was better than them.
After centuries of research, he finally realized he could force turmoil in the world, activate mount, seize control of it and use it to conquer Aand and become God Emperor of the world - something all the gods wanted but had to give up when they formed their alliance. He began studying the enchantment on the mount to determine exactly what would trigger it's release the quickest. He came up with the below actions that needed to be done but found that if he did them completely himself, it wouldn't work. He'd have to enlist help.
- Let demonic energy seep into the world (opens a tear to Yeenoghu's realm on Dbitja; also uses this as a way to attract groups of adventurers he could use for his purposes).
- Take a piece of an Outer Plane to the Material Plane (obtain sediment from the River Styx to trade to the Raven Queen)
- Obtain a memory from the Shadowfell (Travel to the Shadowfell in order to obtain the location of a Book of Keeping)
- Steal a Book or Keeping from an auction in the City of Doors. Will suggest hiring a yugoloth mercenary.
- Retrieve the magic items that contain the essence of each of the 9 gods.
- Make a deal with an Archdevil in order to kill a Demon Prince.