Wikipedia
Ayyappan ( Malayalam: അയ്യപ്പന് Tamil: ஐயப்பன் Sanskrit: अय्यप्प) also known as Dharmasasta, Maṇikanṭhan or Sasta, is a Hindu deity who is the son of Harihara, fused with both Shiva and Vishnu. He is generally depicted in a yogic posture, wearing a jewel around his neck, hence named Maṇikaṇṭhan, which literally means "person with gem around the neck".
By the 20th century, there has been an increase in the number of worshipers of Ayyappan from many different groups, spurred by vast improvements in transport and communication in southern India.
Ayyappan's annual festival is a time of pilgrimage for ever-growing numbers of men from throughout South India. The most prominent and famous Ayyappan shrine is the one at Sabarimala, in the hills of Pathanamthitta in Kerala, with over ten million devotees visiting it every year, making it one of the largest pilgrimage sites in the world. These devotees fast and engage in austerities under the leadership of a Periya Swami (one who has undertaken the pilgrimage to Sabarimala for 18 years) for weeks barefoot and then travel in groups to the shrine for a glimpse of Ayyappan. Bus tickets are hard to obtain for several weeks as masses of elated men, clad in distinctive ritual dhotis of saffron, black and light blue colors, throng public transportation during their trip to the shrine.
The name "Sri Ayyappan" is used as a respectful form of address in Malayalam and Sanskrit. The equivalent of Sri is "Thiru" in Tamil. The mantra Swamiye Saranam Ayyappa is translated in English as, "Lord Ayyappa, I seek refuge in you".