Aspect of Denial

"The static clears and your mind focuses in on theirs. You know this voice, you've heard it once before."

This weapon is blessed by the Shadow, a deity of this world, to be wielded by a creature willing to bind to it. It also has the properties of an onyx weapon.

A grandsword is an overly large weapon forged and wielded originally by the giants of Tema, but has over time worked its way into practice with common kith. Onyx weapons are imbued with ancient dwarven shadow magics, and are said to hold "the darkest shadows from the deepest mountain caves". An onyx weapon can cast a selection of spells from it, as well as cause a Shadow copy of itself to appear.
To wield a grandsword you must have a STR score of at least 21 and be proficient with martial weapons. A grandsword has the following special property:

Radial Attack. A creature with the Extra Attack feature may forgo all attacks to instead make a radial attack. This attack has the chance to hit ALL creatures within 5ft of the wielder. The wielder must make an attack roll against each creature in a clockwise manner choosing whichever creature gets hit first. The damage starts as a d12+STR and diminishes 1 die size (d10- d8- d6- d4) for each consecutive attack made. A creature can perform this attack a number of times equal to their STR modifier per Long Rest.

If attuned to the weapon, the user gains the following:

Hexblade. This weapon is your Hexblade. You may have an additional weapon as your Hexblade. This additional weapon must have either the light or ranged property and can not be a heavy weapon. Your Strength or Dexterity become 21 (this happens as part of the attuning process and fulfills the requirement to attune to this weapon). This choice is made when attuning to this item and can be changed at then end of a long rest (beware the 21 STR requirement to wield this weapon). As an action on your turn you can teleport within range of a creature thats under the effect of one of your hexes or similar brands. This ends the effect of the chosen hex or brand.

Spell Slayer. If a creature within range of your weapon casts a spell, you can use your reaction to make an attack on the creature. This attack deals an additional 2d4 psychic damage and the target must make a Concentration saving throw to continue casting the spell. On a failure, the spell has no effect as it fizzles into the shadows.

Onyx Spellcasting. The weapon has a number of charges equal to twice your proficiency bonus +1 (minimum 2). To cast a spell from the weapon you must use the appropriate action and expend a number of charges equal to the spells level. The Spells available to be cast from the weapon are: Dimension Door, Darkness, Misty Step, Find Familiar (limited to bat or lizard form). The weapon recharges 1d4+1 charges at dusk each day. You can use this blade or any other Hexblade you wield as your spellcasting focus.

Summon Duplicate. Onyx weapons can summon a copy of themselves in the offhand of the wielder (if possible). Summoning a shadow duplicate costs a number of charges equal to the wielders proficiency modifier +1. This copy lasts for 1 hour or until dispelled and can be "sheathed" within the original weapon while not being used. The duplicate has no charges.

Proficiency with a Greatsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Slashing, Weapon Property: Reach, Ignore Weapon Property: Two-Handed, Set: Strength Score, creature with a strength or dexterity score of 21, Teleportation, Damage, Buff, Combat, Heavy, Two-Handed, Graze