Kaiju No. 9 is a significant antagonist in the manga series "Kaijuu 8-gou," also known as "Kaiju No. 8." This character is a highly intelligent and cunning kaiju, capable of transforming into a human to infiltrate and manipulate situations to its advantage. Unlike typical kaiju, Kaiju No. 9 exhibits a high level of strategic thinking and is driven by a mysterious agenda that involves clashing with the Defense Force. Its unique abilities and mysterious nature make it a formidable foe, posing a significant threat to the protagonists.