Relenor

Relenor is the author of the Avernic book, a reward from the Demon Slayer quest. Relenor was from Varrock. They summoned Avernic demons, and gathered the knowledge learned from them into the book. He learned much about Pandemonium, the demonic homeworld, and how demons operated. When he was last heard of, he was traveling to Karamja, to try and find the Greater Demons located there. It is assumed he perished there.