In response to this, the US President called on the comic strip heroes (all characters were owned by King Features Syndicate) such as : Flash Gordon, Buck Rogers, Prince Valiant, The Phantom, Mandrake The Magician and Lothar, again along with some characters now basically forgotten. But while the heroes make a valiant effort, it falls to the kid characters to bring Grimsby around and make him appreciate laughter. Once Popeye's spinach is recovered, all escape the self-destructing island, even meeting the President, who delays them while he catches up on his Sunday Funnies favorites.
If some villains are known mainly by those who oppose them, then Grimsby, while an obscure character, has an illustrious prisoner and hero list many better known would envy.
Four of the heroes opposing him (Gordon, Phantom, Mandrake and Lothar) would, in 1986, form the basis for the animated series, Defenders Of The Earth, meaning Grimsby predated Ming the Merciless in fighting these heroes by fourteen years.