This realization caused the elders of the Clan to grow ecstatic. Wasn't this exactly what they were looking for? An avenue to grow their clan's strength to new, greater heights?
At the same time, while the Mathilde Clan needed things from Nightmare Palace, Nightmare Palace needed things from the elves as well.
Everyone was aware that while devil qi provided great power, it had great drawbacks as well. These drawbacks included a weakening of one's connection to the heavens, making it more difficult to comprehend wills. In fact, this was a large part of the reason devil cultivators were looked down upon.
The only way to fix this problem was to have a soul strength that overwhelmed this heavenly block – which is why Dyon doesn't have this issue – but one can see just how difficult such a task would be, especially without the proper techniques.