Myrkul

Myrkul was the fictional God Of the Dead in the Forgotten Realms campaign setting based upon the Dungeons & Dragons universe.

Summary
In the Dead Three Myrkul was the 2nd to choose from Jergal's powers. Since Bane, the 1st to choose, had chosen to rule over Strife, pain, etc., Myrkul tried to one-up him by choosing the Domain of the Dead, so that enventually Bane's subjects would become his. During the Time Of Troubles, in which Lord Ao (The God of the Gods, to put it simply) kicked out all the Gods from the Planes, where they were forced to take on mortal Avatars, Myrkul and Bane teamed up to storm a Celestial Stairway (an ever-changing "stairway to heaven", granting access to the Planes from the Realms).

When Bane's avatar was destroyed during a fight with the legendary mage Elminster in the Temple Of Lathander in the city of Shadowdale, Myrkul had his temple's wizards locate the shards of his power. Three of his wizards died in the process due to the unstable nature of magic in the Realms, which is why Myrkul ventured into the Border Ethreal (since none of the Gods had lived in the Border Ethereal before the Arrival, Lord Ao didnt see any reason to have Helm blockade it). This made it much easier to locate Bane's being and to reform them into a whole again. If not for Myrkul, Bane may have actually "died" that day in Shadowdale. Bane lost most of his followers and his power, and Myrkul mysteriously gained those followers.