Báirseach

This elegant armoured coat is made from exquisite cloth of grey and white adorned with silvery draconic runes which glow the corresponding colour of the caster's chosen elemental preference. Light silver armour with a draconic symbol adorns the chest beneath the coat, with a fine silver scale mail tunic. Created for a champion of the Draconic Pantheon in the far past, it brims with wild magic and contains the soul of the dragon, Draig, who created it. The item is one of the Relics of the Great War. The wearer must have some physical connection to the Draconic races to wear this coat, or will be unable to use any of its abilities. You gain these benefits while wearing the coat:

• If you aren't wearing chest armour, your base Armour Class is 15 + your Dexterity modifier.
• You have advantage on saving throws against spells and other magical effects.
• Your spellcasting ability increases to 25.
• You gain resistance to lightning damage.
• If worn for 30 days or longer, the soul within the garment bonds with the wearer, creating a permanent connection.

Enaid Draig: As an action, the wearer uses creates a spectral image of the Ancient Blue Dragon, Draig, that surrounds it, encasing the wearer in lightning and granting the abilities of said dragon. The spectral dragon lasts for 1 minute. The wearer gains immunity to lightning damage for the duration. At the end of each of the wearer's turns, the spectral dragon can make one bite attack and two claw attacks against targets of the wearer's choice. Alternatively, the dragon can use a breath attack, this can be used once per transformation. These actions have the same attack bonus, reach, and damage as an Ancient Blue Dragon's bite, claw and breath attacks. This ability recharges upon a rest. 

Tàirnach: As an action, the wearer can condense a portion of the magical energy surrounding it to attack a target of choice remotely, without any components, casting Lightning Bolt. The spell is cast as though using a 9th-level spell slot and deals 49 (14d6) lightning damage. This ability can be used twice on a rest.

Notes: Set: Unarmored Armor Class, Advantage: Saving Throws, Bonus: Spell Attacks, Bonus: Spell Save DC, class with the ability to cast spells, Buff, Warding, Outerwear