Banchajanna's death was now in the hands of Saleen, and Saleen's icy sight had accurately pinpointed Banchajanna's weak point. It was the scepter. Once Saleen released his divine spell and wiped out Banchajanna's remaining soul flames, the connection between Banchajanna and the scepter would be completely broken.
There was a part of Banchajanna's soul within the scepter, but that fragment of soul could only become another soul at best.
Banchajanna had formed a plan to break free from the scepter long ago. If he angered a god, he would be able to fully die. The gods may not have been able to destroy the fragments of soul within the scepter, but they would be able to cut their contact with him completely.
Saleen could see Banchajanna's fear as well. He was a little surprised. So someone as powerful as him could feel fear too?