It is often assumed that Narasimha avatara was taken for the purpose of killing Hiranyakasipu. But, in fact, the Lord took His half-lion, half-man form to protect His devotee Prahlada, said M.A. Venkatakrishnan in a discourse. Because protecting Prahlada required the killing of the demon, the Lord killed Hiranyakasipu.
In the Vishnu Sahasranama, Narasimha avatara is extolled. The twenty-first name Narasimha vapuh is explained by Parasara Bhatta thus: in order to protect His devotee, He assumed the Narasimha form at His will. If we worship Him, He gets rid of the hurdles in our path. The next nama is Srimaan, and this means that the Narasimha form was lovely. It was a unique form with a combination of different species of living things — man and lion. And yet, it did not look odd. The combination of the two forms was perfect. In fact, it was so beautiful that anyone who had seen this form of the Lord would henceforth not find an individual man or lion good looking. Independently, they would not have the charm of the combination of the two forms in Narasimha.
Kesava is a reference to Narasimha’s beautiful hair. In a lion, it is its mane which gives its majestic look. Andal celebrates Narasimha’s mane with the words Veri mayir. Amrtyuh, the 200th name, means that He is an enemy of death itself, since He is death for the god of death. Narasimha is sarvadrik, because He gives to friend, foe and a neutral person what each one deserves. Prahlada is His bhakta, and so He gets Narasimha’s blessings in full. Hiranyakasipu is an enemy, and is killed. The celestials are neutral. They do not take sides in the fight between the Lord and the demon. They just make sure that they applaud the winning side. To them, the Lord gives back their territory, namely devaloka.