Agga-Groo is the foreman of the goldworkers who live in Zog's undersea castle.
He is lean and lank, and his expression is more surly and unhappy than any of Zog's other slaves. He is bored with the repetitive life he leads, but acknowledged it may be better than being dead.
Agga-Groo used to work in Calcutta, India before his ship was wrecked at sea. He was nearly drowned, but Zog rescued him and made him a slave.
When Zog imprisoned Aquareine, the Mermaid Queen asked Agga-Groo to make her a golden sword. At first the goldsmith refused, but Cap'n Bill offered him a collection of trinkets from his pockets, including his steel pocket-knife, and finally Agga-Groo agreed. (The Sea Fairies)