Origin story
After Narasimha slew Hiranyakashipu, his fierce energy would not subside, and the gods feared it might consume the worlds. Lakshmi came to him, and her presence calmed the lord; the two are then worshipped together as Lakshmi Narasimha, the protector who grants both safety and prosperity.
The fierce lion face beside the gentle goddess shows the balance of justice and mercy. In Kerala and Tamil Nadu this form is honoured at family shrines and at temples where devotees come for protection from enemies and for the wellbeing of the household.
Source: Wikipedia: Lakshmi Narasimha — https://en.wikipedia.org/wiki/Lakshmi_Narasimha