When Lucian entered the Secret Realm, he was just an ordinary Qi Gathering Realm cultivator, like 99% of others who entered.
But now, after advancing to Foundation Establishment, his body naturally emitted a powerful Spiritual Pressure. He also didn't have any special disguise technique to suppress or hide his cultivation.
So low-level beasts with limited intelligence, who couldn't use Qi Sense still detect him as anything other than prey. And when they could finally sense his powerful aura, it was already too late.
However, Cultivators were fundamentally different. No matter how hard he repressed his aura, it would never be as perfect as if he used a technique.
So once they entered a certain range around Lucian, they could feel the pressure emanating from him instinctively.
Additionally, their Qi Sense was unable to see through him, making them even more wary and cautious.
