As for why he didn't use his body qi, it was because he had decided to focus on refining his body first. This would increase his foundation instead of raising his cultivation, which he was satisfied with. Once he felt he couldn't refine his body any more without increasing his cultivation, only then would he use it.
But now, the fact he hadn't used these energies had become a blessing.
A pleasant feeling overwhelmed Dyon as his Divine Pulse slowly formed, vibrating his meridians as though giving him a massage.
At first, he panicked. He could already sense his cultivation technique attempting to seal off his soul and energy once more, but that was when he unleashed what he had hidden within his Seal.
