Ketu is generally referred to as a "shadow" planet. He is considered as Tail of the Demon Snake.
It is believed to have a tremendous impact on human lives and also the whole creation.
In some special circumstances it helps someone achieve the zenith of fame.
He is Tamas in nature and represents supernatural influences.
Ketu brings prosperity to the devotee's family removes the effect of snakebite and illness arising out of poisonous matter entering one's body
He grants good health, wealth, cattle and all around prosperity.
Persons afflicted by Kethu dosham are stricken with fears of dacoity, bad habits, loss of property, loss of face, putra dosham.
By praying to Kethu Bhagavan, one can be rid of the doshams.
Motcham, sight, property, land, gold, vehicle, fame, wife, children, happiness, unexpected property gains are the beneficial aspects of Kethu Bhagavan.
Knowledge, business, leprosy, poisonous bites are the aspects of this planet.
Keezhperumpallam sthala varalaru, dosham and remedial measures
The sthalam of Kethu is Keezhperumpallam, which is located 6 kms from Thiruvengaadu, enroute to Poompuhar.
His wife is Chitralekha.
The presiding deities are Naaganaadaswamy and his consort Ambal.
He faces the North-West direction.
The Adi Devatha is Chitraguptan and the Prathyathi Devatha is Brahma;
his colour is red and his vahana is the eagle;
the grain associated with him is khollu;
the flower - red alli (lily);
fabric - multi coloured cloth;
gem - Vaidooriyam (cat's eye);
food - rice mixed with khollu powder.
This place is also called Vanagiri.
Kethu prayed to Naaganaadhaswami and was blessed and rid of his sins by Lord Siva.
It is rare to find Kethu with his head.
At this sthala, he can be seen worshipping Naaganaadhaswami with his folded hands held high.
Mythology
The devas and asuras churned the Paarkadal to obtain amirtham that would free them from death, keeping them alive for ever.
When the amirtham emerged, Lord Vishnu in the guise of Mohini was distributing the amirtham only to the devas.
He was worried that the evil deeds of the asuras will increase multifold if they consumed amirtham.
Realising this, one of the asuras with the help of the asura guru Sukrachariyar, took the form of a deva and consumed the nectar.
Suryan and Chandran who noticed this, complained to Lord Narayana.
In anger, Lord Narayana hit the asura on the head with the spoon in his hand.
The head was cut off and fell on the ground.
But because the asura had consumed amirtham, his head and body continued to live.
The head portion of the asura attached itself to a snake body to become Rahu Bhagavan.
The body portion that was thrown away fell in Pothigai mountain region.
This was found and preserved by a Brahmin.
The head of a snake got attached to the asura body to become Kethu.