What are the five important jobs of Shiva?

Five is a very sacred number for Shiva. His most popular mantra namaḥ śivāya has five syllables. His body is said to have been made up of five mantras: Sadyojāta, Vāmadeva, Aghora, Tatpuruṣha and Īsāna. These are also represented as the five faces of Shiva, just like sometimes Shiva is represented as having three heads for the Trimurti. These five are also associated with the five senses, the five elements, the five organs of perception and the five organs of action. http://www.theshivaexperience.com/what-are-the-five-important-jobs-of-shiva