Kala Samhara Murthi, is a form of Lord Shiva. Since Lord Shiva had killed Yama, he is known as Kala Samhara Murthi. Lord Yama is the death god, and once when the life of Markandeya had ended, he sent his divine attendants to take away his life. But they could not do that, since the great Markandeya was performing puja to the Shiva Lingam, and also embracing it.
Then Lord Yama himself visited the place, and when he tried to put his deadly weapon pasha on the neck of Markandeya, accidentally, it fell on the Shivalingam, and as a result, Lord Shiva had emerged from the Lingam, and with great anger, he destroyed Lord Yama with his third eye spark, and he also made Markandeya to live permanently in this world. Then after the requests of the demigods, Lord Shiva restored the life of Lord Yama, and asked him to continue with his work.
This incident was happened in the present day AmruthaGateswarar Temple situated in Thirukadaiyur, near Kumbakonam, and the Devi in this temple is known as Abirami.
Abhirama Bhattar was a great poet and a staunch devotee of Ma Abirami, who served as a priest in the AmruthaGateswarar Temple during the 18th century AD, and he had written wonderful poems in praise of the divine mother, and the collections of these poems are known as Abhiramianthadhi.
Lord Shiva removes the death related fear from our mind, and gives cheerfulness and pleasantness in our lives. He is the one who used to destroy the evil from the world, and safeguard the good ones. He took the avatar of Sarabha and pacified Lord Narisimha, when Narasimha had become very wild, even after killing the terrible demon Hiranyaksha.
Shiva also drank the HalaHala poison and protected the universe. Through his divine dance, he is maintaining peace and prosperity in this world. He also granted left portion of his body to Ma Parvati, and proved that both of them are same and contain equivalent powers. His powers are unlimited and we cannot describe his significance fully, since he controls the entire universe through his great powers.