Shiva is the Supreme Creator
Shiva, without any origin or end, is the supreme creator of the universe. He is the only one to be above the bondage of life and death, and the controller of time. He is root and cause of universe; still is inert and inactive. Long before any thing existed there was darkness – complete and omnipresent darkness. Then Shiva thought of universe …
Universe needed a force to run it and somebody to manage it. Shiva separated his Shakti (power) from himself and started the creation. Shiva and Shakti created Vishnu to manage the universe. Lord Vishnu created Brahma whom he entrusted with the job of Creation. Vishnu himself became preserver. Then Lord Shiva incarnated as Rudra to act as the Destructor. Thus the Triad was formed to handle Creation, Perseverance and Destruction which formed a cycle. Shiva decided the life of the entire universe including Triad. The Life span of universe is termed as "Kalp-Chakra" the largest measure of time known to world. (Of late science calculated the average life span of universe which is very close the Kalp-Chakra). At the end of a Kalpa, Shiva disposes the entire creation and starts the re-construction of it which invariably starts with the constitution of the Triad.
Shiva, the supreme creator is formless and is represented by Lingam (See Mystery of Shiva Lingam) and is pronounced by universal syllable Aum ? .
Ardha-nar-narishwar
To Create the Universe, Lord Shiva separated his power (Shakti) from himself. Shiva represents the Masculine power, while Shakti the feminine. Since both masculine (Shiva) and feminine (Shakti) are part of him, shiva is known as Ardh-Nar-Nari-shwar (God who his half male and half female).
When Brahma started creating the universe, he found his creations would die out someday and he would require creating again. He failed to think of a way so that the process of creation could go on itself. Then he turned to Lord Shiva for advice. He worshiped Shiva for long time. Pleased with his devotion; Shiva appeared before him. He took a special form – half of which was male and another half was female. He hinted Brahma to create a reproducing specimen. He also hinted on equality of male and females for the creation. This form of Shiva was popularly termed as Ardha-narishwar form.
Shakti is an inseparable part of Shiva. Shakti represents the feminine aspect of Shiva; in fact the creation. Shiva and Shakti complement each other. There is no existence of Shiva without Shakti or Shakti without Shiva. Shiva is inactive. Shakti is the dynamism of Shiva. Shiva merely plans; it is Shakti that executes. So what is the relation between Shiva and Shakti?
Shiva is the cause; Shakti is the action.
Shiva plans; Shakti executes.
Shakti is the conscious mind; Shiva is Subconscious mind.
Shakti is brain; Shiva is the heart.
Shiva is Brahma; Shakti is Sharaswati.
Shiva is Vishnu; Shakti is Laxmi.
Shiva is Mahadevaa; Shakti is Parvati.
Shiva is water in ocean; Shakti is the wave.
Let us elaborate our last point. Shiva-Shakti is like ocean. Shiva is the water and Shakti is the wave. What is wave? It is water in motion. It has not existence with water itself. And water without wave or motion is stale water. Similar is the relation of Shiva and Shakti.