The Black Door

On a wall or within a door frame, create an invisible and undetectable marker with your voice. Placing a marker doesn't spend a spell slot. Placing a second marker dispels the first marker. The caster has the option to dispel the marker without creating a new one.

If the caster is within the max range of the spell and the walls around the caster don't prevent teleportation, then a door can be drawn using the chalk. While drawing, the caster takes a flat rate of 15 necrotic damage, ignoring resistance. Once drawn, The Black Door links the wall of the caster to the marker and a spell slot is expended. The caster can freely touch the door without taking additional damage. The Black Door vanishes when the caster or any creature closes the door and locks the deadbolt. The door does this automatically when the timer expires.

Any creature that is not the caster that touches the door itself (and not merely passes through) must make a CON saving throw. Upon failure, the creature is dealt 3d10 necrotic damage (without ignoring resistance). Upon success, the creature only take 1d10 necrotic damage.

At level 5, The Black Door's Max Range increases by 500 ft (to a net range of 1,500 ft)

At level 10, the max range of the area is increased by 500 ft. (to a max range of 2,000 ft). The Black Door can also be linked through dimensions if the caster is still within range. Opening The Black Door through dimensions causes the caster to be dealt a flat rate of 30 necrotic damage (without resistance) instead of the same-dimension rate of 15 damage. Creatures, other than the caster, that touch The Black Door through dimensions must make a CON save at disadvantage. Upon failure, the creature is dealt 5d10 necrotic damage. Successful saves deal 2d10 necrotic damage.

At level 15, The Black Door's Max Range increases by 500 ft (to a net range of 2,500 ft). The Black Door now has the ability to access a personal a pocket dimension. This dimension exists as a void flatland with no light. The only thing that exists within this dimension is the door frame with which the dimension is accessed with. Access to this dimension can only be done with the original caster's spell, although, escape from the dimension can be done any time with the correct spell. Creating the pocket dimension takes a one-time donation of 100 points of health from the caster. This donation of health can be done in separate times (ie, donate 20 health on one day and 10 another time) so long as the total donation equal 100 hp. Damage is considered necrotic, ignoring resistance. After creating the pocket dimension, each access of The Black Door dimension only costs 10 necrotic damage.