The reason Long Dangdang exposed this potent fusion ability was, naturally, for a purpose. He wanted all the Sacred Legates to see that even if they later found out they didn't possess the ability to fully harness this special power, it was enough. Even if he is just at the 7th rank? What's going to happen when he grows into the 8th or 9th rank?
And the result was that he succeeded - and it was a great success.
The Sacred Legates spectating, including the six Hall Masters of the 6 Great Sacred Temples, seemed somewhat silent. They initiated this Great Impartation Contest to identify inheritors ready for succession and to foster them. But now, their feelings seem a bit off. They were meant to find inheritors, so why does it feel like they are being surpassed? What's going on?
Without dwelling on it, just the prowess exhibited by the quarter-finalists is beyond what an average professionist at the same or even higher level could possess. Each one of them is shining brightly.