The leader of the Blue Dragons whom descended from Zardine. Cromm Cruaich, well known as the Dragon of Death, Devil of Destruction, the God of Utter Destruction, or the God of Unending Darkness, was a creature that once terrified Erinn and was known to destroy everything in plain sight. It plays a major role in Generation 3 and 8.
- Although Cromm Cruaich is listed as the leader of the Blue Dragons, its skin color is more brown than blue.
- When completing the Zardine's Artifact Collection Book (2011) from the Belita's Ancient Artifact Map (2011) gachapon, a cutscene will play and Cromm Cruaich will appear, giving the player a special reward from one of five boxes.
- Despite their interaction in G3, it is mystery that why Milletian did not recognize the Cromm Cruaich in G8. This is possibly due to the Korean director changed the storyline and made a huge plot hole for Cromm Cruaich. While this dragon was mentioned again as a 'God of Unending Darkness' in Generation 9, this proves that the G8's Croom Cruaich behavior is different than G3 and G9.