Jiang Li had already suspected that there was something wrong with the Master-Servant contract in the Lingxi World. Back then, he was uncertain, but after closely observing today how the humans in the Lingxi World nurtured their contract beasts, he confirmed the authenticity of these contracts.
The contracts signed between humans and beasts were indeed Master-Servant contracts, but the Beast Tamers were the servants and the contract beasts were the masters.
That's why he let Xia Chao sign a Master-Servant contract with him.
Xia Chao was his servant.
The reason why humans could sense spiritual energy's existence indeed came from the Master-Servant contract. But the process wasn't as people imagined - forming an intimate connection with the contract beast and enhancing people's perceptive abilities.
The truth was that the contract beasts, as potential powerhouses, gifted a part of their perceptive abilities to their human Beast Tamers.