Siva did not know how many years he had lived for.
A millennium? Eons? It was difficult to tell how the time passed when one was made of just bones.
Although this place was his eternal resting place, he was not absolutely confined to it. He could leave and come back as he pleased.
However, in order to better contain his curse, he had to come back every once in a while.
When he had a mission to complete for the master, he would leave. Once he was done with the mission he would come right back to rest on his rather comfortable chair.
He has once been a great Celestial being, ruler of a vast territory in the myriad realms.
He had been felled eventually.
Most Celestial beings would have had their body turned into God Ash, and their souls would reincarnate after they had gathered up enough Divinity.
But he was not so fortunate.
His curse made it so that his former identity was burned away to oblivion.
In other words, an anomaly was created.