The Spell Thief

From publisher blurb:

Rivalries have emerged as the various orders within the One True Faith vie for power and influence. Most Orders try to maintain relationships with at least a few cults outside the One True Faith that have aligned interests. Some even secretly affiliate with gnomes or other races suspected of threatening the One True Faith’s status. Sometimes these rivalries and affiliations give rise to situations where only great heroes can prevent a sectarian war. A Dungeons and Dragons® 5th Edition Adventure for 1-8 ninth level characters. Episode three of the Cults and Orders Adventure Arc.