Staff of the Spectral Mage

Staff, legendary (requires attunement by a spellcaster)

Crafted from ethereal wood and adorned with haunted gems, this staff is insubstantial and seems to shimmer in and out of existence, yet it feels solid to the touch.

The staff has 20 charges and regains 1d6 + 4 expended charges daily at dawn. If you expend the last charge, roll a d20. On a 1, the staff becomes a nonmagical quarterstaff.

While holding the staff, you can use an action to expend 1 or more of its charges to cast one of the following spells from it, using your spell save DC and spellcasting ability modifier:

• Mage Hand (1 charge)
• Shield (1 charge)
• Invisibility (2 charges)
• Counterspell (3 charges)
• Greater Invisibility (4 charges)
• Wall of Force (5 charges)
• Chain Lightning (6 charges)
• Ghostly Step (6 charges)
• Spirit Guardians of the Elders (7 charges)

Ethereal Spellcasting. While you are holding the staff, you can use an action to expend 2 of the staff's charges, and choose one spell from your list of prepared spells of 1st level or higher. You can cast that spell as if you were in the Ethereal Plane. The spell can affect targets in the Ethereal Plane and the Material Plane simultaneously.

Ghostly Defense. While you are holding the staff, you have resistance to necrotic damage and force damage, and you can move through other creatures and objects as if they were difficult terrain. You take 5 (1d10) force damage if you end your turn inside an object.

Ethereal Insight. When you hit with a spell attack using the staff, you can expend 2 charges to gain insight into your enemies. Until the end of your next turn, you have advantage on attack rolls, spell attack rolls, and ability checks, and other creatures have disadvantage on saving throws against your spells and abilities.