There are different kinds of devotees also. Some devotee worships the Nārāyaṇa feature, some devotee worships Kṛṣṇa feature, some devotee worships Rama feature, some devotees Padmanābha feature, Nṛsiṁha-deva . . . so there are innumerable devotees and innumerable forms also of Kṛṣṇa. But not these ordinary demigods. No. When Kṛṣṇa says, ye yathā māṁ prapadyante tāṁs tathaiva bhajāmy aham (BG 4.11):
"Any devotee who wants to worship Me in My different features, I offer him in that feature . . ." Just like Hanumān, he was a devotee of Rāma. So there is one verse by Hanumān that, "I know Rāma and Nṛsiṁha and Nārāyaṇa, Kṛṣṇa, is the same. But still, I want to worship Rāma." Just like we, ourself, we know Lord Rāma and Lord Kṛṣṇa the same, but we want to worship Kṛṣṇa.
So different devotees have different inclination to offer his service to different features of God. And therefore He has got innumerable features of the presentation. They are differently named.