Kaijuu Yon-gou was an Identified Kaiju. After its death, it was turned into Numbers Weapon #4, formerly used by Hikari Shinomiya [and currently used by [Kikoru Shinomiya)(https://anilist.co/character/183889/Kikoru-Shinomiya).]
Even as a Numbers Weapon, Kaijuu Yon-gou seems to vividly remember its past user Hikari Shinomiya, [since her ghost is clearly visible to its current user [Kikoru Shinomiya)(https://anilist.co/character/183889/Kikoru-Shinomiya). The Kaiju also seems to be very observational and judgemental with Kikoru.]
