Original: Although it is difficult to convince his fellow Hominidae to follow him, Pitar manages to persuade the patriarchal leader of the clan, Costello, who has taken command from the recently deceased Thorn.
Simplified: Although it is difficult to convince the other characters to follow him, Pitar manages to persuade the patriarchal leader of the clan, Costello, who has taken over leadership from Thorn, who had died shortly before.