Origin

Thule's sorcerers were a sect of great power and influence in ancient Atlantis. His intention was to rule the Kingdom from the shadows. Upon discovering their intentions, King Atlan cast them into another dimension with all his followers. The Coven of Thule took this opportunity to establish its power and rearm in hopes of attacking Atlantis again in the future.

Exiled King, Otherworldly Incursion

After hearing rumors that strange structures were appearing within the kingdom's boundaries, Arthur goes to investigate this question. Upon arrival he observes that a series of alien character structures are appearing and destroying parts of Atlantis, looking like an invasion from another dimension. When he enters the main structure that emerges, he finds in it a series of Atlantean refugees from another dimension led by Extriax.

Upon his return to Atlantis, Aquaman is attacked by Mera for failing to destroy those structures that threaten the kingdom. Pursued by the guard and the Drift, Arthur asks Poseidon for help in dealing with this situation. The Greek god of the seas grants him his trident to fight in this war. Aquaman rescues the different refugees that appear as he destroys the new structures that emerge on Earth and fights against the Atlantean soldiers. In this way he discovers that Thule is an alternative dimension created by King Atlan. Its function was to imprison in it a group known as the Coven of Thule, a group of sorcerers who intended to rule Atlantis from the shadows. In their exile, this group decided to create an invading army to take revenge on the first king of Atlantis.

After escaping from an elite force led by Garth, Arthur tries to talk to Mera about this problem, but only finds out that Mera has been supplanted by Siren, her shapeshifter sister who collaborates with the Coven. With the help of the Justice League, Aquaman attacks Atlantis to rescue Mera and destroy the Coven's intentions. After eliminating the dimensional portals and defeating the invading forces, the Thule refugees are brought to Atlantis as new fellow citizens.