Suelivain was a wizard and shadowcaster, practicing both traditional arcane magic and shadow magic. He merged both in the path of the noctumancer. He was familiar with, but did not use, Shadow Weave magic.
Suelivain was dwelling in Thultanthar when a shadowstorm struck and he lost several of his possessions, including the tome of Suelivain. His things were spread across the Plane of Shadow. Unbeknownst to him, however, a rift to the plane later deposited his things in the Halls of Demarch in the city of Tantras in Faerûn.
Members of Demarch's Folly found the tome of Suelivain and from it they learned the fundamentals of shadow magic. They tracked down Suelivain and returned his tome and other possessions in exchange for training in the ways of shadow magic. Suelivain accepted and joined Demarch's Folly in the role of mentor and leader. He educated them in the differences between shadow magic and Shadow Weave magic. He was still with them by 1374 DR.