Kaiju Juu-gou is an Identified Kaiju who attacked Tachikawa Base. It is created by Kaijuu Kyuu-gou and is considered a "prototype".

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It was then weaponized into Numbers Weapon 10, currently used by Soushirou Hoshina.

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Its fight with Soushirou Hoshina managed to excite it so much that, even after being defeated, it still felt linked to Soushirou and wished to be turned into a weapon for him, to fight with him once more. Kaiju Juu-gou seems to be a rather independent individual, easily betraying its progenitor Kaijuu Kyuu-gou just to get closer to Soushirou.

Kaiju Juu-gou is a extremely powerful Identified Kaiju, with a fortitude level of 8.3 when it first appeared,

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and 9.0 after growing larger in size.