If Rowan's ability to access powers of higher dimensions was also due to his status as a dimension was unknown, but it must surely play a great part in it.
According to the Principality, the fourth dimension gave one the capability to control Time, the fifth dimension was Space-Time, and the Sixth dimension was Space-Time and MInd-Memory.
This was the highest knowledge known to the Principality, for the Wills of higher dimension was a secret known to extremely few individuals in all of creation. Rowan considered how lucky he was to come across the fragment of the Mountain and Sea Realm, and wondered what sort of war was responsible for shattering a world that was controlled by a seventh-dimensional Will Holder.