Shankara is the dispeller of all doubts. By his dynamic response to our prayers, He destroys all our doubts, and stabilizes our faith in Him.
There is a saying that a destroyer of the properties of Siva, will get destroyed by Siva. Here the properties of Siva means not just the non living things but include the living things also. This constitutes that one who disturbs a devotee of Siva will get ruined. Rama since he took an avathar as a human he underwent many troubles that a normal human will undergo as per the law of karma. The latter part of Rama’s life after the killing of Ravana is miserable. One of the reasons for the miseries is the bramahathi dhosha he obtained by killing a devotee of Siva, namely Ravana.
If Brahma is the creator, Vishnu the preserver, Siva is the destroyer. His duty is to destroy all the worlds at the end of creation and dissolve them into Ekanda, nothingness.
Modern theories of space do suggest the possible ending of the physical universe after some billions of years through the expansion of a gigantic black hole devouring the matter from endless galaxies.
Before the worlds really come to an end, Siva has many things to do to keep the worlds going. His first and foremost task is to destroy many things in order to ensure the cosmic harmony (Rta) or the order of the universe.
Siva’s destruction is not negative. It is a positive, nourishing and constructive destruction that builds and transforms life and energy for the welfare of the world and the beings that inhabit it.
He destroys in order to renew and regenerate. His destruction is for the construction like a mother does cooking to feed her children. Through destruction he facilitates the smooth transitions of things and events from one stage to another.
He destroys our imperfections in order to ensure our spiritual progress. He destroys our illusions, desires and ignorance. He destroys our evil and negative nature.
He destroys our old memories, so that we can move on with the movement of time. He destroys our relationships, attachment, impurities, physical and mental wrong doings, the effects of bad karma, our passions and emotions and many things that stand between us and God as impediments to our progress and inner transformation.
And in the end when we have made sufficient progress, when we are ready and prepared, and when we are willing without any inner conflict, he destroys death.