The Lost Arcana

You have bound your pact not to a sentient entity, but to a rare, pristine pocket of the uncorrupted Weave. This anomaly preserves magic in its primordial state—an era before arcana was fractured into rigid schools or polluted by mortal cataclysms. Accessed through a mundane-looking codex that remains completely blank to all but your touch, this ancient power manifests as tangible, silent glyphs of compressed, pearlescent energy. As a channeler of this forgotten arcana, you draw upon the primordial source code of the world, enforcing the original, unblemished rules of reality to protect yourself and unravel the magic of your foes.

Forgotten Arcana Features
Level 3:  Forgotten Arcana Spells, Secret of the First Script, Lattice Ward
Level 6:  Echoes of the Forgotten Weave
Level 10:  Pristine Absorption
Level 14: Guardian's Apotheosis

Level 3: Secrets of the Weave

You unlock a foundational secret from outside the traditional Warlock curriculum, drawing from the pure potential of the uncorrupted Weave.

Choose one 1st-level spell of your choice from the Wizard or Bard spell list. It can belong to any school of magic. You always have this spell prepared, it counts as a Warlock spell for you, and it automatically scales with your Warlock Pact Magic slots.

You learn one additional spell of your choice from the Wizard or Bard list when you reach Warlock levels 6, 10, and 14. Each time you gain a new spell from this feature, it can be of any level up to the maximum level of your Warlock Pact Magic slots (up to 3rd-level spells at level 6, and up to 5th-level spells at levels 10 and 14).

10th Level Secret

Choose one spell of your choice from the Wizard or Bard spell list. It can belong to any school of magic and can be of any level up to the maximum level of your Warlock Pact Magic slots (up to 5th-level spells). You always have this spell prepared, it counts as a Warlock spell for you, and it automatically scales with your Warlock Pact Magic slots.

14th Level Secret

Choose one spell of your choice from the Wizard or Bard spell list. It can belong to any school of magic and can be of any level up to the maximum level of your Warlock Pact Magic slots (up to 5th-level spells). You always have this spell prepared, it counts as a Warlock spell for you, and it automatically scales with your Warlock Pact Magic slots.

3rd Level Secret

Choose one 1st-level spell of your choice from the Wizard or Bard spell list. It can belong to any school of magic. You always have this spell prepared, it counts as a Warlock spell for you, and it automatically scales with your Warlock Pact Magic slots.

6th Level Secret

Choose one spell of your choice from the Wizard or Bard spell list. It can belong to any school of magic and can be of any level up to the maximum level of your Warlock Pact Magic slots (up to 3rd-level spells). You always have this spell prepared, it counts as a Warlock spell for you, and it automatically scales with your Warlock Pact Magic slots.

Level 3: Arcane Aegis

You can shape the raw residual energy of your uncovered secrets into a protective, translucent barrier of pure arcane energy.

When you cast a spell gained from your Secrets of the Weave feature using a spell slot, you manifest a protective lattice ward around yourself. The ward has a maximum number of hit points equal to twice your Warlock level + your Intelligence modifier.

Whenever you take damage, the ward takes the damage instead. If the damage reduces the ward to 0 hit points, you take any remaining damage.

Whenever you cast any Warlock spell of 1st level or higher using a Pact Magic spell slot while the ward is active, the ward regains a number of hit points equal to twice the level of the slot expended. The ward cannot regain hit points above its maximum, and it dissipates entirely when you finish a Long Rest.

Forgotten Arcana Spells

The Forgotten Arcana lets you choose from an expanded list of spells when you learn a Warlock spell. You gain the following spells at the Warlock levels listed.

Once you gain a patron spell, you always have it prepared, and it counts as a Warlock spell for you. Furthermore, you can cast one of your prepared 1st-level spells from this table once per Long Rest without expending a spell slot.

Forgotten Arcana Spells
 Warlock Level | Spells 
3rd: Shield, Disguise Self, Misty Step, Invisibility |
5th: Counterspell, Major Image |
7th: Banishment, Hallucinatory Terrain |
9th: Wall of Force, Mislead |

Level 6: Echoes of the Forgotten Weave

You learn to channel the feedback of broken magic to punish your enemies. When you successfully prevent, mitigate, counter or dispel a spell cast by a creature within 60 feet of you with abjuration magic, or when a creature within 60 feet of you fails a saving throw against a spell you cast, you can use your reaction to unleash a backlash of raw arcana.

The target takes force damage equal to your Warlock level + your Intelligence modifier. Additionally, if you have an active Arcane Aegis, it regains hit points equal to the force damage dealt, up to its maximum capacity.

You can use this feature a number of times equal to your Intelligence modifier (minimum of once), and you regain all expended uses when you finish a Long Rest.

Level 10: Weave Absorption

Your understanding of the fundamental laws of magic allows you to seamlessly unravel incoming elemental energy and weave it directly into your defenses.

You gain resistance to force damage. Additionally, whenever you take damage from a spell, you can use your reaction to gain resistance to that damage type until the start of your next turn.

When you use this reaction, your Arcane Aegis (if active) instantly regains a number of hit points equal to your Warlock level + your Intelligence modifier.

Level 14: Master of the Forgotten Weave

You have achieved absolute synchronization with the foundational currents of magic, allowing your protective barrier to become an engine of pure arcane dominance.

While your Arcane Aegis is active, you gain the following benefits:

- You have advantage on saving throws against spells and other magical effects.
- Your Warlock spells ignore half cover and three-quarters cover when targeting a creature.
- Once per turn, when you deal damage to a creature with a Warlock spell or a subclass feature, you can add your Intelligence modifier to the damage dealt.