Great Sky Demon Dragon Gaiking (大空魔竜ガイキング, Daikū Maryū Gaikingu) was a Super Robot mecha anime series produced by Toei Animation, credited as an original idea by Akio Sugino. However, in reality the original idea was of Go Nagai. Toei deliberately took Nagai out of the credits in order to avoid the payment of royalties. Because of that, Nagai sued Toei and stopped further collaborations with Toei for a long time. The legal battle lasted more than 10 years. Nagai himself confirmed that he was the creator of Gaiking in the Comicon 2007 in Naples, Italy.