Lord Subramanya is an incarnation of Lord Siva

Lord Subramanya is a ray born of the Divine Consciousness of Lord Siva

They represent the power of action and the power of knowledge respectively.

He is a Godhead easily accessible in this dark age of ignorance and lack of faith

He gives material and spiritual prosperity and success in every undertaking of His devotees, even if they show a little devotion to Him.

He is worshipped with great devotion in South India.

Lord Subramanya's other names are Kumaresa, Kartikeya, Shanmukha, Guha, Muruga and Velayudhan.

Lord Krishna says in the Gita: "Among the army generals, I am Skanda".

Lord Subramanya holds a spear in His hand, just as Lord Siva holds the trident. This is an emblem of power.

It indicates that He is the ruler of the universe.

His vehicle is the peacock. He rides on it. This signifies that He has conquered pride, egoism and vanity.

There is a cobra under His feet, which indicates that He is absolutely fearless, immortal and wise.

Valli is on His one side, Deivayanai on the other

The six heads represent the six rays or attributes, namely, wisdom, dispassion, strength, fame, wealth and divine powers.

They indicate that He is the source of the four Vedas, the Vedangas and the six schools of philosophy.

They also indicate His control over the five organs of knowledge as well as the mind.

Skanda Shashti celebrates the day when a great demon called Taraka was defeated.
Skanda Sashti falls in November. It is the day on which Lord Subramanya defeated the demon Taraka.

Tarakasura, was oppressing the celestials. He drove them out from heaven. All the gods then went to Brahma to appeal for help
Brahma said to the gods, "O Devas, I cannot destroy Taraka, as he has obtained My Grace through severe penance.
But let Me give you a suggestion. Get the help of Cupid, the God of Love. Induce him to tempt Lord Siva, who remains absorbed in His Yoga Samadhi.
Let Lord Siva unite with Parvati. A powerful son, Lord Subramanya, will be born to them. This son will destroy the demon that harasses you."

Indra, the chief of the gods, thereupon requested Cupid to go with his wife, Rati, and his companion Vasanta (the season of spring), to Mount Kailas, the abode of Siva. Cupid carried out the instruction at once, for it was already springtime. Standing behind a tree, Cupid shot his arrow of passion towards Siva, whilst Parvati was placing some flowers in His hands.
The moment their hands met, Siva experienced a distracting feeling. He wondered what it was that disturbed His Yoga.
He looked around and saw Cupid crouching behind the tree.
The Lord opened His "third eye", the inner eye of intuition, and Cupid was burnt to ashes by the fire that emanated from it.
That is why the God of Love is also called Ananga, which means "bodiless".
After burning Cupid, the Lord ascertained by His Yogic vision that the birth of Lord Subramanya was absolutely necessary to destroy the powerful Taraka.
Siva's seed was thrown into the fire which, unable to retain it, threw it into the Ganges, which in turn threw it into a reed forest.
This is where Lord Subramanya was born; hence, He is called Saravanabhava--"born in a reed-forest".

Shanmukha became Kumara - the powerful virile adolescent who was also the beautiful and the handsome ( Muruga) .
He was made the General (Deva Senapathi) of the God's army. "Skanda received from his mother Parasakthi an all powerful Vel (lance).
Hence He is also Sakthi Velan. He engaged the armies of Simhamukha, Surapadman and Tarakasura on a six day battle and vanquished all of them on the sixth day. The Asuras were annihilated and the Devas were liberated. The sixth day (Sashti) of the waxing moon ( sukhla) in the month of Ashada ( Oct/Nov) is celebrated as Skandha Sashti
Indra was restored to his kingdom and gave his daughter Deivayanai or Devasena marriage to Skanda.