Rowan could not merge with his bloodlines due to his present state, where he had to restrict himself to the third-dimensional level, to make sure his presence left no ripples in space.
He was digging the foundations of power from under a Primordial, and any slight carelessness would lead to his discovery. His bloodlines were intelligent enough to understand what was happening without any need for him to explain.
So they had to share their memories with him, else he could only listen to Serathis speak, and as lovely as her voice sounded to the ears, Prime was correct when he said they did not have the time for this. Barely eight years remain before his promised duel with Primordial Demon, and he was not ready for that challenge.
