Circlet of the Sharpened Mind (Patreon)

Wondrous item, very rare (requires attunement by a creature with an Intelligence of 17 or higher)

This iron circlet has a magical pearl at its center and can hold up to 4 gemstones. When found, the circlet has 2 gemstones. A gemstone worth at least 5,000 gp can be added to the circlet over the course of 1 minute as it's magically drawn and fastened into place. While wearing the circlet, you can take a special Attack action on your turn to summon a number of floating, spectral swords equal to the number of gemstones in the circlet and make one melee spell attack with each of them against a target within 10 feet of you. You are proficient with these attacks and use Intelligence as your spellcasting modifier for them. On a hit, the target takes force damage equal to 1d8 + your Intelligence modifier. The swords appear at your side and remain there until you dismiss them as a bonus action or until you fall unconscious or remove the circlet. While the swords are summoned, you can take this special Attack action on each of your turns. The spectral swords shed bright light in a 10-foot radius and dim light for another 10 feet.

You can replace one of these melee spell attacks with a weapon attack as part of this special Attack action. If you're able to make multiple attacks with the Attack action, you can replace any number of these spell attacks with up to the amount of weapon attacks that you can normally make with the Attack action.

When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to make one melee spell attack with one of the summoned swords against the creature, rather than making an opportunity attack.

While the fighters held the blade, I was busy studying it. Its curves, its construction, its true name and purpose. While those brutes knew how to swing a tool of war, I became war itself.