Legendary Horned Harbingers were those followers of Myrkul who continued to practice our faith following his demise during the Time of Troubles and the Avatar Crisis. They were all unique in the fact that at one point of their life or another, they had each touched the artifact known as the Crown of Horns, which carried the essence of the "deceased" Myrkul. Thus showing his death, time amongst the dead and restoration was all by his own design.
Harbingers developed powers and were granted the use of magic from the Death domain, learned how to reanimate dead bodies over long distances, and could both rebuke as well as create undead creatures. As they grew in power, Harbingers gained control over undead thralls at a rate unknown to typical clerics. Horned Harbingers were selected from divine or arcane spellcasters, but most were expert necromancers or undead. While some of them had begun to worship other deities associated with death, such as Jergal, Cyric, and even Kelemvor, they all returned to the rightful worship of Myrkul.
Horned Harbingers grew a circlet of horns out of their heads, which somewhat resembles the Crown of Horns.
If any of the church are ever able to be in the presence of one, they must show the respect Harbringers deserve as the Chosen Dead of Myrkul.