Origin story
To rescue Rama and Lakshmana from the underworld, Hanuman took five faces — Hayagriva, Narasimha, Garuda, Varaha and his own — and blew out the lamps that guarded the demon Ahiravana's citadel. The five-faced form is invoked for protection from negative forces and for courage in difficult times.
The five faces also stand for the five directions, so that Hanuman guards the devotee on every side. The Panchamukha Hanuman shrine is worshipped with the same devotion as the single-faced god, and the tail, the mace and the fiery eyes remind the devotee of the power that serves with humility.
Source: Wikipedia: Panchamukha — https://en.wikipedia.org/wiki/Panchamukha
