Timeless Rip

Starting at 17th level, As an action you can spend 4 ki to rip open a portal of space and time on a target up to 40 ft away. The target must make a constitution save, if failed they are reduced to 0 hit points, if they success they take 8d10 necrotic damage. If used while the 6th rift is open, on a failure they are pulled into the portal lost to space and time; if they succeed they take an additional 12d10 damage, this closes your rift immediately.