Narullian (Familiar Book Imp)
Book imps are masters of knowledge, dispatched by the powers of the Abyss to offer advice to and tempt mortal spellcasters.
Long ago, Narullian was gifted to a dark wizard who believed in her strength more than she should. With her perishing, he was free, which was intolerable. He sought out other dark forces and found a dark dwarven mage, who took him in. This dwarf left to the abyss to find more power and took Narullian with him. The dwarf found the beholder, Bolvagon, and presented the imp as a gift.
When trapped in the Abyss, Petrin Iceblade encountered Bolvagon. The beholder was imprisoned and needed the Dragonborn to set him free. Petrin negotiated with Bolvagon and the beholder presented Narullian in return for freedom. Petrin agreed, receiving the imp, but then betrayed the beholder, leaving it stranded in the Abyss.
Petrin wondered why the beholder, who could read his mind and must have sensed his intentions, would part with the imp. As it turns out, the imp is a vessel of Bolvagon’s essence and his arrival in the world strengthened the beholder’s influence there.
The Eldarin noble Kimath It-Arist told the group that Narullian is one of the four remnants of Bolvagon. Should the heroes wish to destroy the accursed Book of Years they must first destroy the four remnants. For now, Narullian is kept alive because he can lead the party to the other remnants.