Book of Lost Secrets

Origin Feat

You gain the following benefits once you have the following Prerequisites: Level 5+ Warlock, Pact of the Tome eldritch invocation.

Arcane Archivist. You can now inscribe magical rituals in your Book of Shadows. If you come across a spell in written form, such as a magical spell scroll a wizard's spellbook or another warlock book of shadows, you might be able to add it to your ritual book. The  spell's level can be no higher than half your warlock level (rounded up), and it must have the ritual tag. The process of copying the spell into your ritual book takes 1 hour per spell, and costs 50 gp per level. The cost represents the material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it.

Weave Proficiency. While you are in possession of your book of shadows you gain an additional pact slot that is of 1st level and remains at this level not following your regular pact slots progression as you level up.