Gaya's instincts told her the beastman in front of her shouldn't be underestimated. Hence, she transformed into her true form which enhances her power by multiple folds.
Any weak-minded person would have been scared to death if they had seen Gaya's true form. She was terrifying with her shining dark purple scales, the two long fangs, the blood-red eyes with pitch-black vertical pupils. Except Jacobe wasn't a weak minded person at all. In his life of hunting criminals and wrongdoers, he dealt with countless terrifying people who were more terrifying than her. Apprehending a criminal didn't completely depend on the cultivation stage. If it did, he wouldn't have been able to catch criminals more powerful than him.