As Heisei stated to Nisshō as she caused the reaction, it takes the principle of the Truth-Seeking Balls to the pinnicle as it grows larger by devouring chakra. This along with its properties as a large Truth-Seeking Ball is that while it drains chakra it also destroys virtually all physical matter that comes into contact with it by draining it dry. This coupled with its size and power have caused it to be classified as a Kinjutsu, however Nisshō wouldn't care either way.