Fan Zhongtang is a Elder from the Black Sect and can even be considered the number 2 just behing the sect master.
He chose to bet on Nanbei Chao after the Qi Province Tournanment and betray the Black Sect. First, trying to kill Jiang Chen with his grandson Fan Kun to take merits so when Nabei Chao became the ruler of the Qi Province he'll get high position. Later in the ultimate war between the four sect, he intentionnaly broke the Black Sect formation leading to the death of many disciples and elders of the sect. Then he turned side an joined force with Burning Sky Pavilion and Heavenly Sword Sect to kill his own fellow sect members. But unlucky for him, Nanbei Chao got defeated by Jiang Chen and he then became a member of the losing side. After the war, he got judged by the Black Sect and Jiang Chen, he begged for forgiveness, even lying it was because his grandson got killed and he wanted revenge. But Jiang Chen revealed the truth that he already had betrayed the sect long before that. Jiang Chen then asked Yu Zihan to kill him. Yu Zihan purposely did it slowly, cutting his neck bit by bit, prolonging time so that Fan Zhongtang could slowly taste the entire process of dying.