Technology & Combat Characteristics
It's design for aquatic combat and does poorly on land. The turtle shell is actually a specially-made core lander. It's armed with cucumber-shape beam saber.
History
The Kappa Gundam was a mobile fighter constructed by Neo Japan. Though not a participant in the 13th Gundam Fight, it was one of the countless machines fielded as part of the Gundam Federation's response to the Devil Gundam's seizure of Neo Japan.
According to Only! My Gundam description, it was representative of Neo Japan during the 11th Gundam Fight, but later ends up in the hands of Neo Denmark some time before the 13th Gundam Fight.