Lord ShivaLord Shiva (friendly one) is not found in the Rigveda, he is the oldest Gods of India.
The first name found in the Vedas is Rudra. Rudra is above all a violent God, the God of storms and destruction, who is also feared by the other Gods. Shiva manifestations can be roughly be divided into five categories:
The young ascetic
The comsmic danger
The lord of destruction
The terrible Bhairava
The benevolent protector and loving husband
Shiva-Dakshina-Murit or Mahayogi is one of the well known illustrations of Lord Shiva. He is seated on top of the Himalayas in deep meditation. The God is represented wearing tiger skins. He wears a moon sickle in his hair and snakes coil around his neck. In his hands he holds a trident and drum and his attributes includes a water jug. His face is turned South (dakshina) the direction which brings luck. He is the great teacher who reveals to Gods and Holymen the essence of sacred text and the lord of music. In this function he represented sepreately as Vinadhara-Murti standing or sitting with a lute (vina). The cosmic dance of Shiva (Nataraja) is seen as the symbol of the movement of the universe. The circle of the flames around shiva is energy in it purest form, but also the fire of cremation. The dwarf under Shiva's foot represents ignorance. The drums symbolizes combination of the male and femlae aspects. The sound indicates source of creation. The fire in palm reveals his ability to destory the universe, and his hand put out in the gesture of an elephant represents his strength while raised foot represents libreation. The dancing Shiva is also depicated in other positions as Lalatatilakam, eight or sixteen arms, one leg dance on Apasmara, while other is stretched straight up. As Tandava ten arms dancinf esctasy on place where bodies are cremated accom[anied by Devi and a host of spirits.

In Shiva's aspect of the destroyer he is force with manintaining the cycle of destrcution and creation. He is death which contain life.
Gajasura-Murti
Dancing on teh head of an elephant demon. This demon was disrupting the rituals of number of Brahmans were warshipping Shiva's lingam. Shiva stepped out of the lingam, chopped off the demons head and wrapped the demon's skin around him like a cloak.
Tripurantanka-Murti
The hero who was the only one to destroy the three cities of Asuras when demons gained much Power.
Bhairava (Terrible One)
The best known terrifying mainifestation of Shiva. He can be identified by the hair surrounding his head with fire and his dogs accompanying him. He wanders round naked covered only in ashes. The story goes as follows. The God Bharama desired his own daughter. He was so obsessed by her that he gave himself a countenace facing each directions, so he could watch over her. The daughter fled to heaven and Bhrama created a fifth face so he could watch her there also. This made Shiva so furious that he appeared as Bhairava and chopped off Bhrama's fifth head. In punishment for his sin Bhairava was forced to wander through the universe begging and half mad with remorse holding Bharma's skull in his head, until he had atooned for his terrible deed by bathing in the holy pool in Varassi. Sometimes wandering Shiva is depicted in a less terrifying way and he is tehn known as Kankala-Murti. Shiva as a beggar is the only God to wear footwear, viz sandals. As a God who has been cast out, Bhairava is revered particulary by the coutcastes, the untouchables.
Mahadeva
The greatest of all Gods. The three Gods of the Trimurti are all seen as aspect of Shiva. The three faces of this figure represant creation, preservation, and destruction.
Sadashiva
The enternal Shiva, aslo known as Panchanana (Five Face). In this creation it represent five cosmic acts: creation,preservation,destruction,concealment,and salvation.
Nandi
The White Bull, Shiva's ride. As an independent deity the bull was in ancient times of Lord of joy (Nandikenshvara), Joy,music, dance were seen as the fundamental forces of creation an aspect which was later transferred to Shiva. later it was said of Nandikenshvara was a rishi who gurarded Shiva's door to become divine in this way.