C501 Tai chi
Gu Masters are also divided into many factions, they also have their own unique system.
Normally, powerful Gu Masters would have special imprints on their Gu techniques, referred to as Gu prints.
If a Gu Master killed someone, then it was very easy to determine which Gu Master did it from the dead person.
Of course, this was only confirming the Gu Master's sect, as for who did it, no one knew