Vowing To The Heavenly Daos

"Vow to your skill?"

Xie Yang, Feng Yuhuan, and Shen Xiage were startled. They had heard of many other ways of making an oath. One of the most common ones was to vow to Heaven, but it didn't always work as Heaven had no eyes and no ears. It couldn't pick up the oaths.

Then, there was the Void Contract where one vowed on their soul and spirit. Failure to keep the vow would stop one from not being able to enter the Void World.

Other than that, there were also the vows to the Daos. In this particular case, one's Daos would be used to form into seals in their body, breaking the vow would trigger the Dao seals and totally destroy their cultivations from within, including their Dao hearts.

However, Zhong Yue's request of them vowing to his skill, it was the strangest way of making an oath they have ever heard in their entire life.

Is this some kind of trick?