Significance of Lord kartikeya
When the five elements governed by Lord Shiva (Panch Mahabhoota – Earth, Water, Fire, Air and Ether) united with Shakti (Pure Consciousness), Lord Kartikeya was born.
Shiva is called Panchaanana – Lord with five heads. These five heads represent the five elements in Nature.
When these five elements united with the sixth: Chaitanya Shakti(Pure Consciousness), they gave birth to the Shadaanana (six headed), also called Lord Kartikeya.
You can understand this in terms of the Kundalini Shakti (the primordial, dormant yet potent energy said to be present in a coiled form at the base of the spine).
We have seven chakras (energy centers) within us. When the energy surges through the six chakras and stabilizes at the sixth chakra – the Ajna chakra (present in the middle of the eyebrows), it blossoms as Lord Kartikeya (symbolism of the Guru Tattva -Principle).
The Ajna chakra is the place of the Guru Tattva. It is where the Guru Tattva blossoms and manifests itself. And that Guru Tattva itself is Kartikeya Tattva.
Lord Shiva is the un-manifest Divinity, while Lord Kartikeya is the manifest. So you can think of Lord Kartikeya as symbolic of the Kundalini Shakti.