1. One performing severe austerities and the great yogi
Shiva is always seated in a Bandha or a mudra. His temperature rises due to heat generated by performing severe austerities; Hence, He uses the Ganga, the moon and serpents which endow a cooling effect and lives on the snow-clad Kailas mountain.
If someone disturbs His meditation, the radiance generated by spiritual practice will be suddenly expelled and whoever is in front of Him will not be able to tolerate it and get destroyed. This is referred to as being 'reduced to ashes by Shankar's opening of the third eye'.
3. One who is willing to undergo any distress for the sake of imparting happiness to others
The poison generated during the churning of the celestial ocean (Samudra Manthan) was burning the entire Universe, but no deity came forward to accept it. At that time Shiva drank that poison and saved the world from destruction.
4. One who has both, deities and demons, as his worshipers
Neither did demons like Banasur, Ravan, etc. Worship Lord Vishnu nor did Lord Vishnu bestow any boon upon any demon. However, they worshipped Lord Shiva who blessed them.
5. Master of the spirits
Since Lord Shiva is the master of spirits, his worshipers are generally not possessed by them.
See how Lord Shiva enhances your life with his powerful blessings on the auspicious occasion of Maha Shivratri which will have special significance in our life. Performing Rudrabhishek destroy all kinds of negativity from our life and also enhance all-round prosperity and happiness in life by the powerful blessings of Lord Shiva.