The story of demon Narakasura is found in the various
Puranas including Bhagavatam. It is also mentioned in the Mahabharata.
Narakasura was killed by Satyabhama, an incarnation of Goddess Bhu Devi. Please note that it was not Sri Krishna who killed Narakasura.
Demon Narakasura had got a boon that He will only be killed
by his mother. Sri Krishna to annihilate the demon took the help of Satyabhama,
a manifestation of Bhu Devi who was the mother of Demon Narakasura.
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