Coros was a proto-dragon of blue-green coloration and an old rival of the blue-white Malygos. They had competed in the past over kills, territory, and strength.
One day when dozens of proto-dragons were hunting in the same area, Coros and two of his companions attacked Malygos. Though outnumbered, the grey proto-dragon Neltharion came to Malygos's aid, establishing a friendship between the two and driving Coros and his companions off.
Later, when the massive Galakrond was devouring proto-dragons, Coros cut off Malygos and hid in a crevasse his rival had intended on hiding in, leaving Malygos open to being attacked by Galakrond. Like the other proto-dragons Coros rallied under Talonixa's command and quickly gained her favor as evidenced by her allowing him to hunt by her side and even agreed to tentative peace with Malygos due to threat Galakrond and the not-living posed to their race..
Despite seemingly to agree with Talonixa that the proto-dragons should rally and destroy Galakrond Coros encouraged Ysera, who grew more vehement in her distaste for violence, in preaching her belief of peace to the other dragons. However while Ysera seemed to seek a return to the status quo, Coros preached in finding a way to live under the rule of Galakrond. When Ysera attempted to convince Talonixa to seek peace Coros left her standing her alone as he sough to deflect focus away from him, though Malygos noted if Ysera convinced the majority Coros would suddenly appear beside her.
At some point during the meeting Coros and his companions vanished and following the meetings end, an uneasy Malygos began to search out for them. After locating his rival Malygos discovered to his shock that Coros, in an attempt to gain protection from Galakrond had started to emulate him by practicing cannibalism and encouraged his companions to do the same. After being attacked and killing one of Coros's companions Malygos continued to secretly follow him and while hidden bore witness to Coros betraying the rest of proto-dragons by informing Galakrond of when Talonixa planned to attack the great beast. After seemingly leaving Galakrond quickly returned when Coros and his remaining companions took flight and devoured one, while Coros rammed the other to buy him time to escape. Despite this Galakrond gave chase perhaps viewing Coros as a threat, simply wanting to sate his hunger, or both, and devoured the smaller dragon.
- "Do it! Must be done this way! Galakrond did it this way!"
- "Now... now you see how Galakrond will not eat us! We are like Galakrond! We will be with him! He will not eat us now!"