Son of Shiva and Parvati, married with Valli and Devasena.

Karttikeya is the brother of Ganesha, who is the firstborn, Karttikeya is the young son, Kumara.

Karttikeya was created to destroy the demon Taraka.

His mount is the peacock (mayura) Parvani, a son of Garuda. His weapon is the lance, Vel. The emblem of his banner is the cock.

Karttikeya is his name, because his mothers were the six Krittikas, the pleiades. For them he let himself grow six heads.

Other names
As Subrahmanya, he is the Knower of the Absolute, Brahman.
As a God of war, his name is Skanda.
Because he was found in the reeds,  he is called Sharavanabhava.
As the six-faced, his name is Shanmukha.
He is Kumara as the young son.
As Swaminatha he is the Lord of the Lord.
As Velayudha he is the one whos weapon is the lance.
Murugan is his name in Tamil Nadu and in Kerala.

Read about Karttikeya here