Safer∙Sephiroth is the final boss in Final Fantasy VII. Being the last of Sephiroth's forms, this is his most powerful transformation. This battle is penultimate, but is considered the last challenge in the game, as it is followed by a plot-related battle that cannot be lost. The song "One-Winged Angel" plays during the battle against Safer∙Sephiroth; a reference to Sephiroth's right arm being replaced by a single dark wing.