The Center Sect and the Green Mountain Sect had been competing with each other for many years for the orthodox leadership, so it was natural for them to pay attention to each others' styles. The old man was well aware of the energy revealed by the sword style of Green Mountain. As such, when Jing Jiu came out from the pond by riding the sword, he had already recognized that Jing Jiu was a Green Mountain disciple, and deduced Jing Jiu's identity after some inference.
"The Green Mountain Sect has actually sent someone to contact the Underworld Emperor; do you intend to collaborate with the Underworld?"
The old man sneered, "Yeah, that evil man had already collaborated with the Underworld before, so this is the tradition of your Green Mountain Sect."
No Cultivation practitioner could accept the accused crime of collaborating with the Underworld.