Arcanum Infinitum (arr-kan-num in-fi-nigh-tum)
An Instruction Manual on Magic
The Arcanum Infinitum is a vast collection on the knowledge of magic and its uses. It is also proof that any creature can utilize magic in some way. Spellcasters will obviously have an easier time when using the book.
This tome is sentient for the purpose of aiding the reader. Because of the arcane wards, it can only be affected and destroyed by taking damage from a spell of 6th level or higher that is not psychic or poison damage. If it is destroyed, it reconstructs in the library of the Venezian Consiglio.
Invoking the Book. A creature can use an action to open the tome and call out what they would like to do with magic or what spell they would like to cast. The tome will then flip through pages to a chapter that best fits what the reader would like to do for casting a spell.
Spellcasting Through the Tome. A creature can cast any spell as a ritual with the book but spells requiring greater power are far more difficult to cast because of the complex and difficulty of following the instructions to do so. Failure to follow the instructions as intended can have devastating and unseen results. A creature makes a spellcasting check using their Spellcasting ability plus their proficiency bonus. See the table below for the base DC on casting a spell.
The following factors also impact the casting DC for the creature using the tome:
| Spell Level | Casting DC |
|---|---|
| Cantrip | DC 12 |
| Level 1 | DC 13 |
| Level 2 | DC 14 |
| Level 3 | DC 16 |
| Level 4 | DC 18 |
| Level 5 | DC 20 |
| Level 6 | DC 22 |
| Level 7 | DC 24 |
| Level 8 | DC 26 |
| Level 9 | DC 28 |
Mishaps in Casting. On a failed save, it is implied the casting creature failed to follow the instructions properly. The tome will then close itself to the creature until the next dawn for that creature’s safety from using it further. The tome may also close itself if it is being used by the same caster for their safety after casting difficult spells twice with it.
A mishap that occurs can vary wildly. You can roll on the Magic Surge table in the Wild Magic Sorcerer table or take ideas based on the school of the spell that was casted:
Abjuration. The creature becomes irritated by a terrible ringing sound, causing disadvantage on Perception checks. A cocoon of energy may envelope the caster, causing them to only have 10 feet of movement unless a creature helps roll them along.
Conjuration. Something else may be conjured or additional things are conjured.
Perhaps 2d6 creatures related to the conjuring, such as 2d4 imps if conjuring fiends or mephits with elementals.
Divination. The caster and those around it receives strange visions for 1d4 hours +1 per spell level.
The creature might take 2d8 psychic damage plus an additional 1d8 per spell level.
Enchantment. The creature may become charmed or frightened of the next creature it sees.
The caster will follow the command of the next creature it hears.
Evocation. A blast of energy related to the spell cast deals 2d8 damage plus 1d8 per spell level.
Illusion. The caster will see odd things that are not there.
Necromancy. Spirits of the dead haunt the caster for 2d6 hours.
Transmutation. The appendages of the caster also become twisted into unnatural shapes such tendrils or claws.
The environment around the changed target may change into a slick or jagged area either permanently or for 2d4 hours.
History
The book was penned by the Venezian mage Ardalio Karcetti. He was inspired by the vast utilities magic could be used in and wanted to create a book that even those who struggle with wielding the ways of magic could use. Ardalio then went around all of Florenelle to collect what magic lore he could both from Calvoran traditions and of the Consulate’s teachings. This would include even Arkengrath’s necromancy.
Ardalio helped found the Empire of Venezia and his legacy is forever cherished and taught in their arcane traditions. To ensure it stays preserved, the book is bound to the library of the Consiglio should it ever be destroyed.
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