Jack-in-the-Green is a possible name for the god Atlan.
However, some scholars believe this name actually refers to Logaan, the Trickster god. Jack-in-the-Green has acted as a messenger between Titan and heroes. Also, he describes himself as the "Ancient King". He could be referring to the King of Atlantis before the First Battle, explaining how that land got its name. However, in Gallantaria, where this Messenger is revered, there are barrows that are said to be the burial mounds of the Ancient Kings of that area.