Erasing Me

You brandish your weapon in an attack against a target within range as you reach closer to becoming one with the void. After this attack you sheathe your weapon (which is still considered held) and enter a special stance, while within this stance you are concentrating as if you would any other spell that requires concentration. This stance may be exited after reducing the creature hit by this attack to 0 hit points. While within this stance you inflict Sinking with every attack you make and may replace any damage you deal for the duration with cold damage. Any space you enter for the duration of this spell is converted to Void space indefinitely.

At the start of your turn for the duration of this spell you must make a Charisma saving throw, on failure you lose proficiency in 2 skills and languages. If you cannot lose anymore skills and languages, you lose proficiency in all weapons. If you cannot lose proficiency in weapons, you lose the ability to take an action, bonus action or reaction (your choosing.) If you cannot take anymore actions of any kind, you fall unconscious and lose all memories which cannot be regained by any means short of the Wish spell. At the end of every long rest, you regain one proficiency or action of your choosing lost from this spell.

Note: Sinking is a Status effect that works as follows. Sinking is a stacking status effect, when a creature with a count of Sinking makes an attack roll, ability check, or saving throw with disadvantage and misses their attack or fails their saving throw, they take an additional amount of damage equal to their Sinking count whenever they miss an attack roll or fail an ability check or saving throw and their maximum hit points are reduced by the amount of damage taken. Additionally a creature within Sinking has a penalty to hit when making an attack with disadvantage equal to their current Sinking count. When a hostile creature that the afflicted creature can see is reduced to 0 hit points, all stacks of Sinking are removed.