BOOK OF EIBON
• You gain a +2 bonus to your Spell Save DC.
• You may cast the plane shift spell once per day.
• You have advantage on Arcana, History, and Religion skill checks.
• Your spells may ignore the vulnerabilities of aberrations and treat their immunities as vulnerabilities.
"The book is supposed to have been written by Eibon, a wizard in the land of Hyperborea. It was an immense text of arcane knowledge that contained, among other things, a detailed account of Eibon's exploits, including his journeys to the Vale of Pnath and the planet Shaggai, his veneration rituals of Zhothaqquah (Eibon's patron deity), and his magical formulae—such as for the slaying of certain otherworldly horrors. "