In Hinduism, Lord Kartikeya is regarded as the Commander-in-Chief of the Gods. He is especially worshipped in South India. Lord Kartikeya is the Son of Lord Shiva and Goddess Parvati. His devotees also worship Him by various names such as Skanda, Shadanana, Kumara, Parvatinandana, Shivasuta and Gauriputra. Lord Kartikeya is worshipped for the attainment of power, courage and valor. By His grace, one gains leadership qualities, military bravery and the power of guidance. During His childhood, Lord Kartikeya was nurtured by the wives of Saptarishis, i.e., the Seven divine Sages.

According to Hindu beliefs, Lord Kartikeya was brought up by the wives of the Saptarishis, who are known as the Kritika. Since He was nurtured by the Kritikas, He came to be renowned as Kartikeya.
According to Skanda Purana, in ancient times there was a demon named Tarakasura who became extremely powerful after receiving a boon from Lord Shiva. As per this boon, Tarakasura could be killed only by the son of Lord Shiva. Due to Tarakasura's atrocities, chaos prevailed in all three worlds. All the Gods approached Lord Vishnu to overcome this calamity. Lord Vishnu advised them to seek refuge in Lord Shiva, because the end of that wicked demon was possible only through Shiva Putra, i.e., the son of Lord Shiva. All the Gods reached Mount Kailasa and requested Lord Shiva to beget a son.
Hearing the prayers of the Gods, a radiant mass of divine energy emerged from the body of Goddess Parvati and merged into Lord Shiva. At that moment, Lord Shiva opened His third eye, from which a powerful radiance emerged and struck Goddess Ganga. When Goddess Ganga tried to carry that divine essence, Her waters began to boil due to its intense power. Terrified by this, Goddess Ganga placed that divine essence in the Sharavana forest.
Thus, from the radiant divine essence that originated from Lord Shiva's body, a beautiful and delicate divine child was born. When the six Kritikas who were roaming in that forest saw the child, maternal affection arose in their hearts and they came forward to breastfeed Him. As soon as they approached, the child manifested six faces. Thereafter, they took the child to Kritika Loka, i.e., the realm of the Kritikas and began nurturing Him.
Sage Narada informed Lord Shiva and Goddess Parvati about this entire incident. Both became eager to meet their son and went to the Kritika Loka. On seeing Her son, Mother Parvati was overwhelmed with maternal emotion. Lord Shiva and Goddess Parvati then explained the entire story to the Kritikas and returned to Kailasa with their son. Since He was nurtured by the Kritikas, He became famous throughout all the worlds as Kartikeya. Later, during the war between the Gods and demons, Kartikeya led the divine army and destroyed the demon Tarakasura.
Lord Kartikeya is depicted as Shadanana, meaning one with six faces. He is portrayed with Svarna Varna, i.e., golden-complexioned and Ashtabhuja Rupa, i.e., eight-armed. In most depictions, Lord Kartikeya is shown along with His two consorts. In South India, Lord Kartikeya is worshipped as Lord Murugan. Lord Murugan is depicted as a young boy with a gentle and charming smile on His face. He is shown riding a peacock and wearing a crown adorned with peacock feathers. One of His hands is in Varada Mudra, i.e., the gesture of blessing, while another holds a spear or arrow-like weapon. In many temples, Lord Murugan is depicted with six faces.
Lord Shiva, the Lord of the three worlds, is the father of Lord Kartikeya and Goddess Parvati is His mother. Lord Ganesha, the first to be worshipped among all Gods and Lord Ayyappa are His brothers. It is believed that Goddess Ashoka Sundari, Goddess Manasa and Goddess Jyoti are considered His sisters.
According to descriptions found in the Skanda Purana, Lord Kartikeya is a Brahmachari, i.e., celibate and hence unmarried. However, according to beliefs prevalent in South India, Devsena and Valli are considered His two consorts. Devsena is the daughter of Devaraja Indra and is also worshipped as Chhathi Mata. While Valli is considered the daughter of the king of Kishkindha. The peacock is the vehicle of Lord Kartikeya. Sage Jaratkaru and King Nahusha are His brothers-in-law and Maharshi Astika is His nephew.
General Mantra -
ॐ श्री स्कन्दाय नमः।
Om Shri Skandaya Namah।
ॐ श्री सुब्रमण्यम स्वामिने नमः।
Om Shri subramanyama Svamine Namah।
Kartikeya Gayatri Mantra -
ॐ तत्पुरुषाय विधमहेः महा सैन्या धीमहि।
तन्नो स्कन्दः प्रचोदयात॥
Om Tatpurushaya Vidhamaheh Maha Sainya Dhimahi।
Tanno Skandah Prachodayata॥
or
ॐ कर्तिकेयाय विद्महे षष्ठीनाथायः धीमहि।
तन्नो कार्तिकेय प्रचोदयात्॥
Om Kartikeyaya Vidmahe Shashthinathayah Dhimahi।
Tanno Kartikeya Prachodayat॥