Aegis of the Tempest

A dark sapphire crystal suspended within an intricate frame of blackened silver. Tiny veins of blue-white energy occasionally move beneath the surface of the gemstone like lightning trapped inside a storm cloud.

The Aegis does not create conventional armor.

Instead, it reacts to the user's instincts.

When danger approaches, the crystal pulses before you have consciously recognized the threat. Fleeting arcs of blue lightning race across your body as an invisible field of arcane energy forms around you.

Arcane Aegis:

While you aren't wearing armor, your base AC becomes:

13 + your Dexterity modifier

This does not stack with Mage Armor or another alternative AC calculation.

Lightning Reflex:

1/Long Rest

When an attack hits you, you can use your reaction to instinctively activate the Aegis.

You gain:

+3 AC against the triggering attack.

Must be used before damage roll.

This can cause the attack to miss.

The bonus applies only to that attack. 

If the attack misses because of Lightning Reflex, blue-white electricity erupts across your body before disappearing.

Notes: Set: AC Max Dex Unarmored Modifier, Bonus: Unarmored Armor Class, Bonus: Unarmored Armor Class, Sorcerer