Kleptomancer

Kleptomancy is not a practice taught in most institutions where wizards learn to hone spellcraft. This is largely because it is not something that can be studied, so much as a unique talent for studying. Kleptomancers have a particular ability for intuitively sensing and working with the weave. They can perceive echoes of magic left by other spellcasters, and when faced with miscellaneous magical effects have an aptitude for picking them apart and figuring out what makes them tick. In either case, the Kleptomancer gains a measure of mastery over the magic of another, allowing them to utilize it to their own benefit. Through frequent absorption and expelling of magic, their spellbooks gain a semblance of arcane sentience and ravenous magical hunger, and can be deployed as companions.

Spell Thief

When a creature casts a spell of a level you can cast, up to 5th level, an echo of the spell is created at their location known as a spell fragment. These fragment lasts for one hour before dispersing back into the weave. While within 5ft of the fragment, you can appropriate it as a bonus action. When doing so, choose a prepared spell from your spellbook to overwrite with the stolen spell. When this stolen spell is cast, it is removed from your spellbook, leaving an empty space in your list of prepared spells until you prepare new ones at the end of the next long rest you take.

While you have an appropriated spell in your spellbook that appears on the Wizard spell list, you can expend time and currency to add it to your spell list as if it were a scroll.

Hungering Spellbook

As a magic action, you can animate your spellbook. It appears in an unoccupied space within 5ft of you. The Hungering Spellbook is friendly to you, and obeys your commands. See the spellbook's game statistics in the Hungering Spellbook stat block. 

HUNGERING SPELLBOOK

Tiny Construct.

Armor Class 16 (natural armor)

Hit Points 5 + two times your wizard level

Speed fly 30 ft. (hover)

Antimagic Susceptibility. The Hungering Spellbook is incapacitated while in the area of an antimagic field. If targeted by dispel magic, the spellbook must succeed on a Constitution saving throw against the caster's spell save DC or be reduced to 0 hit points.

Damage Resistances. Force damage. Bludgeoning, piercing, and slashing damage from magical weapons.

Damage Immunities. Poison.

Immutable Form. The Hungering Spellbook is immune to any effect that would alter its form.

Magic Resistance. The Hungering Spellbook has advantage on saving throws against spells and other magical effects.

Condition Immunities. blinded charmed, deafened, exhaustion, frightened, paralyzed, petrified, poisoned, prone, unconscious.

Senses. blindsight 60 ft., passive Perception 12

Languages. understands the languages you speak

Challenge — Proficiency Bonus (PB) equals your bonus

Actions

Mana Sap. Ranged Weapon Attack: your spell attack modifier to hit, range 30 ft., one target you can see. Hit: 1d6 + PB force damage. If the target must make a Constitution saving throw from this damage to maintain concentration on a spell, it must be rolled at Disadvantage.

Recall. The spellbook teleports back onto the person of its wizard owner.

Devour Magic. The spellbook consumes a spell fragment within 5ft of it, appropriating it. The spellbook regains hit points equal to the level of the spell appropriated.

In combat, the Hungering Spellbook shares your initiative count, but it takes its turn immediately after yours. The only action it takes on its turn is the Dodge action, unless you use you take a bonus action on your turn to take another action. That action can be one in its stat block or some other action. If you are Incapacitated, the Hungering Spellbook can take any action of its choice, not just Dodge.

If the spellbook is brought to 0 hit points, it returns to its inert form and teleports back onto your person, losing 1d6 spell fragments if it has any stored.

Once the spellbook returns to its inert state, you must complete a short rest before being able to animate it again.

Weave Absorption

Your Arcane Restoration feature is replaced by this feature.

During a Short Rest, you can convert any spell fragments you have appropriated into Wizard spell slots. The level of slot regained corresponds to the level of the spell. For example, you may convert a fragment of a 3rd level spell such as Blink into a level 3 spell slot, a fragment of Armor of Agathys into a level 1 spell slot, and so on. When you do so, the converted fragments leave empty spaces in your spellbook until you prepare your spells again at the end of a Long Rest.

Arcane Plagiarism

Dispel Magic, Remove Curse, and Shield are added to your spellbook for free. They are always prepared, and do not count towards your maximum number of prepared spells. They cannot be overwritten by a spell fragment.

When Dispel Magic ends the effects of a spell cast at 5th level or lower, you can overwrite a prepared spell in your spellbook with its corresponding spell fragment.
When Shield successfully deflects a spell of 5th level or lower, you can instead absorb it, overwriting a prepared spell in your spellbook with its corresponding spell fragment.
When Remove Curse removes a curse from an item, you can overwrite a prepared spell in your spellbook with a spell fragment of that curse to place on another item.

In any of the above situations, the spell fragment created by the appropriated spell is directly added to your spellbook instead of being created at the caster's location, if applicable.

Unleashed Spellbook

As a magic action, you can create a hungering vortex around your spellbook in a 30ft Emanation. While within this vortex, you and your allies have Resistance to damage from spells and other magical effects, and Advantage on saving throws imposed by them, and spell attacks against them have Disadvantage. Foes in the emanation that are concentrating on spells must make a Constitution Saving Throw against your Spell Save DC upon entering the aura, and every time they end their turn within it to maintain concentration on their spells. If a spell or magical effect is negated or ended by the effects of this aura, you may appropriate it to your spellbook as a Spell Fragment, overwriting a prepared spell.

Once you unleash your spellbook, you must complete a Long Rest before using this feature again.

Additionally, you can now fill empty spaces in your prepared spell list with spell fragments, instead of needing to overwrite already prepared ones.