...
Uno kept on attacking until he got used to the state that he was currently in.
He already used the 'White Dawn Boundary' alongside the 'Demonic Qi' to suppress the dark nature that it had. And after being in that state for a long time made him master it.
Now that he was using the 'Black Origin Threshold' to complement the nature of the 'Sacred Qi' and strengthen its powers, he needed to master this particular state to achieve the ideal style that he was planning to achieve.
Naturally, the seed demon could sense what was actually happening and immediately became furious about it. After all, no one would want to be a practice dummy for someone to hone their skills, especially when it was in a middle of a real battle instead of a sparring match.
And to make it even worse, Uno did not only plan this out from the very beginning, but he also been doing it boldly in front of a life-and-death situation where a single misstep could cost his existence.