Shiva has 5 faces. They are Sadyojāta, Vāmadeva, Aghora, Eshāna and Tatpurusha.
When the Sadyojāta face of Shiva is worshipped, all desires get fulfilled. In this form the Lord wears yellow-coloured clothes and passes on kriya shakti (power of action) onto the worshippers.
Through His second face as Vāmadeva, Shiva gives radiance (tejas) and power of knowledge. He is calm, peaceful and is resplendent like fire. He shines in white colour. He showers all prosperity and the results of all their past fruitive actions onto His devotees.
His third face is known as Aghora. In this form, He provides the basic qualities to water, Moon and to coolness. He is the destroyer of all sins of the devotees. He destroys all evil forces and grants all types of prosperity to His worshippers.
The fourth is the form of Tatpurusha. He represents the Atharva Veda (the 4th Veda). In this form He is the Lord of all the gaṇas (Shiva’s attendants), a Rudra to all the physical and mental disorders (ādi-vyādi) and acts as a physician who dispels all diseases.
With His Eshana face, He is the basis for all knowledge, intellect of all the deities and for peace. In His form as Eshana, He resides in several body parts/ organs in the beings and shines with a bright golden glow.
Thus, in these 5 forms, He executes the 5 important duties. He is also the basis for the 5 basic elements and is also the cause for the very existence of the universe!
The various ‘Shadaamnyaaya mantras’ emerged from these five faces. The Purvāmnaya mantras emerged from the Sadyojāta face, the Dakshinamnaya mantras from the Vāmadeva face, the Paschimāmnaya mantras out of the Aghora face, the Uttaramnaya mantras from the Tatpurusha face and the Urdhvāmnaya mantras originated from His Eshāna face.
-Glimpses of Bhaktimala