Sword of the False Hero

A giant sword of Ethereal darkness appears, floating in the air above a point you can see on the ground within range. The sword has a length of 120feet (90 foot blade, 30foot hilt). The blade's tip towers 480 feet above that point, and appears to hang by a single black and red thread extending to the sky.

When the sword appear, each creature within 1 mile that can see it must make a wisdom saving throw or become Frightened.

You must use your action on each subsequent turns to maintain concentration on this spell (if you are Evil alignment roll with advantage). If your concentration ends prematurely, the thread dissipates and the sword falls to the earth. Concentration also breaks if you leave the plane of existence or move beyond the distance of the spell.

Once the thread dissipates the sword begins to fall at a rate of 240ft per turn. When the swords tip hits the ground, its energy is released in a catastrophic blast. Each creature in a 120ft radius from the point of contact must make a constitution saving throw. On a failed save, a creature takes 12d12 Necrotic Damage and 20d12 Force damage, or half as much damage on a save. Creatures within half of the spells radius have disadvantage on the saving throw. Buildings and structures take double damage. Once the swords hits the ground and does damage, it disappears leaving behind a 30ft long, 15ft wide, 90ft deep crater.

The spells power and range increases the longer you maintain concentration. For each minute after the first that you maintain concentration, the radius of the impact and the range increase by 120ft (up to a maximum of 1,200 feet). Additionally, the damage increases by an additionally 1d12 necrotic damage and an additional 1d12 force damage for each additional minute (up to a maximum of 24d12 Necrotic and 32d12 force damage).

If the spell is activated before its full power is reached, the unchallened energy backlashes onto you. You must make a constitution saving throw or take any remaining damage that the would have dealt as necrotic and force damage. On a success you take half.

-What's the point of all this power if one can not simply use it to its fullest potential? - Golgari Grimskull

*Spell idea from AdramastesGM*