Hello, friends! As you know, Dimensional Sieges and Raids are not available on Core as there is no second server to compete or cooperate with. Due to this fact quest "Confronting the Greatest Danger" that requires taking part in Dimensional Raid cannot be completed by in-game means. This problem should be resolved by developers in the nearest future, but I would like to remind you that if you cannot go further to Exalted title without this quest, you can address to Support Service, and we will help you before the official fix from developers arrives. NB: quest "For Victory" can be completed on Core - you can get quest items on normal castle sieges.