Shiva
Shiva is referred to as the good one or the auspicious one. Shiva - Rudra is considered to be the destroyer of evil and sorrow. Shiva - Shankara is the doer of good. Shiva is 'tri netra' or three eyed, and is 'neela kantha' - blue necked (having consumed poison, i.e., Halahala to save the world from destruction). Shiva - Nataraja is the Divine Cosmic Dancer. Shiva - Ardhanareshvara is both man and woman.
He is both static and dynamic and is both creator and destroyer. He is the oldest and the youngest, he is the eternal youth as well as the infant. He is the source of fertility in all living beings. He has gentle as well as fierce forms. Shiva is the greatest of renouncers as well as the ideal lover. He destroys evil and protects good. He bestows prosperity on worshipers although he is austere. He is omnipresent and resides in everyone as pure consciousness.
The five mantras that constitute Shiva's body are Sadyojaata, Vaamadeva, Aghora, Tatpurusha and Eesaana. Eesaana is Shiva not visible to the human eye, Sadyojaata is Shiva realized in his basic reality (as in the element earth, in the sense of smell, in the power of procreation and in the mind). The Vishnudharmottara Purana of the 6th century CE assigns a face and an element to each of the above mantras. ( Sadyojaata - earth, Vaamadeva - water, Aghora - fire, Tatpurusha - air and Eesaana - space).
The names of the deified faces with their elements are Mahadeva (earth), Bhairava (fire), Nandi (air), Uma (water) and Sadasiva (space).
In Shiva temples, Navarha (9 planets), Ganesh, Skantha, Saraswati, Lakshmi, Vishnu, Brahma, Ashtathig balar, Durga, Bairava, and all the other Hindu gods will have the place, denoting the entire gods are uniquely said to Lord Shiva, so that only he is in a shapeless form (i.e. in linga form).
Shiva is not limited to the personal characteristics as he is given in many images and can transcend all attributes. Hence, Shiva is often worshipped in an abstract manner, as God without form, in the form of linga. This view is similar in some ways to the view of God in Semitic religions such as Islam or Judaism, which hold that God has no personal characteristics.
Hindus, on the other hand, believe that God can transcend all personal characteristics yet can also have personal characteristics for the grace of the embodied human devotee. Personal characteristics are a way for the devotee to focus on God. Shiva is also described as Anaadi (without beginning/birth) and Ananta (without end/death).
According to the Bhagavata Purana, Lord Shiva manifested in his multiple forms from the forehead of Lord Brahma. When Lord Brahma asked his sons, the Four Kumaras, to go forth and create progeny in the universe, they refused. This angered Lord Brahma and in his anger a child appeared from his forehead, which split into two - a male part and a female part. The male half started crying inconsolable and as a result, Brahma named him Rudra. The child cried seven more times and each time Brahma gave him a separate name. The eight names thus given to the child were Rudra, Sharva, Bhava, Ugra, Bhima, Pashupati, Ishana, and Mahadeva. Each of these eight names are said to be associated with specific elements of the cosmos, namely the earth, water, fire, wind, sky, a yogi called Kshetragya, the sun, and the moon respectively.
This male child became Lord Shiva, who was asked to go forth and create progeny, but when Lord Brahma observed the power, as they shared the qualities of Lord Shiva, he asked him to observe austerities instead of creating progeny.
A slightly different version is told in the Shiva Purana: in the Shiva Purana, Shiva promises Brahma that an aspect of his, Rudra, will be born and this aspect is identical to Him.
The tale about Lord Shiva being born and immediately splitting into two halves of male and female indicates the origin of the Ardhanarishvara - the union of substance and energy, the Being and his Shakti (force).
Consorts, and the burning of Kamadeva
Shiva's consort is Devi, God's energy or God as the Divine Mother who comes in many different forms, one of whom is Kali, the goddess of death. Parvati, a more pacific form of Devi is also popular. Shiva also married Sati, another form of Devi and daughter of Daksha, who forbade the marriage. Sati disobeyed her father. Daksha once held a Yajna (ritual sacrifice) to Vishnu, but did not invite Shiva. In disgust, Sati burned herself through yogic meditation (or, in another version, in the same fire Daksha used in his sacrifice).
When Shiva's attendants reported the matter, Shiva tore off a lock of his hair and lashed it against the ground. The stalk split in two, one half transforming into the terrifying gana Virabhadra, while the other caused Mahakali to manifest on the scene. The pair immediately led Shiva's army of ganas to Daksha's yajna and destroyed it.
Daksha was decapitated by Virabhadra, but was later given the head of a goat to humble him, once the rishis and Brahma had pleaded with Shiva for lenience. Sati was later reborn in the house of Himavat (Himalaya mountain-range personified) and performed great penance (Skt: Tapasya) to win over Shiva's attention.
Her penance brought Kamadeva and his consort Rati to the scene, whereupon they attempted to interrupt Shiva's meditation with Kamadeva's arrow of passion. It caused Shiva to break his Samadhi, but he was so infuriated by Kamadeva's assault that he burned the deva of passion to ashes on the spot with his glare. It was only after Rati's pleading that Shiva agreed to reincarnate Kamadeva.
Parvati would try again without Kamadeva's aid to win over Shiva, and this time, through her devotion and the persuasion of other rishis, yogis, and devas, he eventually accepted her.
The sons of Shiva
Shiva and Parvati are the parents of Karttikeya and Ganesha.
Ganesha, the elephant-headed God of wisdom, acquired his head by offending Shiva, by refusing to allow him to enter the house while Parvati was bathing.
Shiva sent his ganas to subdue Ganesha, but to no avail. As a last resort, he bade Vishnu confuse the stalwart guardian using his powers of Maya.
Then, at the right moment, Shiva hurled Trishula and cut Ganesha's head from his body.
Upon finding her guardian dead, Parvati was enraged and called up the many forms of Shakti to devour Shiva's ganas and wreak havoc in Swargaloka.
To pacify her, Shiva brought forth an elephant's head from the forest and set it upon the boy's shoulders, reviving him. Shiva then took Ganesha as his own son and placed him in charge of his ganas. Thus, Ganesha's title is Ganapati, Lord of the Ganas.
In another version, Parvati presented her child to Shani (the planet Saturn), whose gaze burned his head to ashes. Brahma bade Shiva to replace with the first head he could find, which happened to be that of an elephant.
Karttikeya is a six-headed god and was conceived to kill the demon Tarakasura, who had proven invincible against other gods.
Tarakasura had terrorised the devas of Swargaloka so thoroughly that they came to Shiva pleading for his help. Shiva thus assumed a form with five faces, a divine spark emanating from the third eye of each. He gave the sparks to Agni and Vayu to carry to Ganga and thereupon release.
In Ganga's river, the sparks were washed downstream into a pond and found by the Karittikas, five forest maidens. The sparks transformed into children and were suckled by the Karttikas. When Shiva, Parvati, and the other celestials arrived on the scene, there was a debate of who the child belonged to.
Further, Parvati, who was the most likely to care for the child, was puzzled as to how she would suckle five children. Suddenly, the child merged into a single being and Shiva blessed him with five separate names for his five sets of parents to settle the debate. The child, despite having been born from five sparks, had a sixth head, a unifying principle which brought together the five aspects of his father's power into a single being.
From here, the campaign in which Karttikeya would vanquish Tarakasura and liberate Swargaloka began.