Wrath of the Righteous
From Staunton’s Journal:
The shadow demon arrived in the possessed body of a crusader named Maranse (a man the diary records as now being long dead after having been turned over to the succubus Kiranda), and bore gifts from a place called the Ivory Sanctum— five elixirs of distilled power brewed from powdered Nahyndrian crystal. The notes explain how Staunton volunteered to take one of the elixirs to test its strength before Aponavicius used one, and of the powers the elixir unlocked in him (drinking the elixir was the antipaladin’s moment of ascension to mythic power). The notes go on to describe the grisly deaths the elixirs inflicted on the dragon and xacarba servants Aponavicius tested them on, and that only the chimera Soltengrebbe survived the transformation. The notes conclude by revealing that the shadow demon Eustoyriax remains here in a chamber below the citadel, where Aponavicius has placed him in charge of protecting the Sword of Valor.