Angel Sanctuary Vol. 3 (manga)

Despite Setsuna's efforts to deny his love for his sister, he can't allow her to leave the country without letting her know how he feels, but how can she feel about love that borders on incest? She may never live to find out, because an angel has been sent down from heaven just for her--just to make sure that she dies! The two demons from hell, Kurai and Arachne, are still trying to bring out the avenging angel in Setsuna, but first they must deal with the mysterious, seemingly immortal Kira. Even if a way is found to bring the angel Alexiel out of Setsuna, can Tokyo survive the transformation?