Is this sentence clear and properly worded?

FYI- Zethrindor is the dracolich and Iyraclea is the Ice Queen. Once they conducted a search of the ruins, the companions realized that the citadel was not the source of the Rage, but the location of a magical gateway. Before Iyraclea recognized this herself, Zethrindor and his flight arrived at the site, and battle was immediately joined between the followers of the Ice Queen and the dracolich.