Who is Tancredi from Sudden Fiction International: Sixty Short-short Stories and what is their importance?

Tancredi is the two-headed child of a deeply religious woman. She initially tries to murder the freakish child, but it insists on surviving. When Tancredi grows up, the two heads develop two personalities. The right head is devout and quiet; the left is vile and dark. The left Tancredi goes to prostitutes, and the right Tancredi whips himself in repentance. One day, the right Tancredi stabs himself with a hat pin. The left Tancredi is enraged and strangles his other head. When the left Tancredi realizes he has killed his right head, he weeps and dies.