Taotie was right to be afraid of Huan Yi's Martial Depth. The natural order didn't allow warriors to exceed certain limits. Different species had different limits, but Huan Yi was a unique case and faced more restrictions than any other life of the Three Realms.
From the moment he was born, the Demon Child lived in the invisible shackles imposed upon him by this mysterious entity—a force that transcended all Realm Wills: Yuanqi.
Also known by the primordials as the Original Breath and Creator, Yuanqi wouldn't allow Huan Yi to exceed its control, and though bound by its own rules, always kept an eye on him.
Seeing that Huan Yi had regained the Tyrant Dragon Blood of his original body, and added to the already outrageous Immeasurable World Bloodline, Yuanqi had no other choice but to take action.