A nightmarish thousands=shards shattered Odachi held together with gravitational forces. The weapon is kept inside a scabbard whose weight has been heavily amplified by gravity, making it almost impossible to lift or unsheathe the weapon. It's rumored that the blade had no difficulty slicing mountains into halves at its prime.

A Gravity-amplified Odachi whose blade has been shattered into countless shards. Attacks made with the weapon deal 4d6 Magical Slashing Damage at touch range. As an attack action, the player can prime the weapon, provided that they possess graviturgy or great telekinesis capability, to instantly perform a wide slash(es) on their next turn for free that deal 2d6 Slashing Damage in a 70 FT Cone and slow their speed by 25 Ft, Enemies who are hit twice by will have their speed reduced to 0. Enemies within the AoE will feels a shift in Gravity before the attacks, allowing them to escape in advance if they know what's coming, if they stay within the AoE until the start of the user's next turn, they must make a Dexterity Saving Throw to avoid the shards, taking halved damage on success. A skilled graviturgy combatant can avoid slashing their own allies through precision.
The AoE sweep can be interrupted by attacking the user of the blade, so long as they fail a Constitution saving throw.

Gravastar Blade: Every successful attacks apply Heavy on the target, causing them to take more damage from Earth based attacks or Attacks which prone them by 1d6. Their speed is also reduced by 5 FT. However, Winds based attack or those that knock them away deal less damage by 1d6.

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

Notes: require attunements by a great capability of telekinesis or graviturgy or 25 Strength or 30 Dexterity and 20 Strength to lift or Unsheathe, Heavy, Two-Handed, Graze