Prahlada Maharaja is describing his position of fearlessness in the presence of such a ferocious form. Prahlada Maharaja is fearless, whereas others who perceive such a form are fearful— especially a nondevotee. Such a form for the nondevotees certainly represents a cause for fear because it represents death. However, Srila Prabhupada has described here in his purport that the devotee who has taken shelter of the Lord is not fearful of this form nor of any other form of the Lord. Krishna states in the Bhagavad-gita that He is immortality and death personified. Therefore, such a ferocious form is certainly a cause for fear for those who have not taken shelter of the Lord.
LFD Vol 3,Fearlessness of the Devotee Pg 124, 3rd paragraph