Aaru Padaiyappa or otherwise the general of the six armies (devas) is Lord Murugan.
Sage Agastya wanted to take two hills Sivagiri and Saktigiri - to his abode in the South and commissioned his asura disciple ldumban to carry them. Idumban was one of the very few asura survivors of the war between Murugan's forces and those of Surapadman. After surviving the war he had repented and became a devotee of Lord Murugan/Skanda.
At this stage, Muruga had just been outwitted by His brother Ganesa in a contest for going around the world and He was still smarting over the matter. Ganapati had won the prized fruit by simply going around His parents, who were His world. Subrahmanya who went around the world in His peacock, came back to find that the prize had already been given away. In anger, He vowed to leave His home and family and came down to Tiru Avinankudi at the foot of the Sivagiri Hill. Siva pacified Him by saying that Subrahmanya Himself was the fruit (pazham) of all wisdom and knowledge. Hence the place was called Pazham-nee ( 'You are the fruit') or Palani. Later Murugan withdrew to the hill and settled there as a recluse in peace and solitude.
On the orders Sage Agastya, ldumban bore the Sivagiri and Saktigiri hills slung across his shoulders in the form of a kavadi, one on each side. When he reached Palani feeling tired, he placed the kavadi down to take rest.
When ldumban resumed his journey, he found that he could not lift the hill. Muruga had made it impossible for ldumban to carry it. Upon one of the hilltop the great asuran spotted a little boy in loin clothes. Idumban demanded the boy to vacate the hill at once so that he could proceed with his task. The boy, who was in a fighting mood, refused.
In the fierce battle which ensued, ldumban was slain. When the wife of the Asura pleaded with the little boy, ldumban life was restored.
Coming back alive, ldumban recognised the boy as none other than his ishta devata Murugan. Idumban prayed to the Lord that whoever carried the kavadi on their shoulders, signifying the two hills should be blessed. Idumban also requested that he should be given the priviledge of standing sentinel at the entrance to the hill. Hence we have the ldumban shrine half-way up the hill. Every pilgrim is expected to offer obeisance to ldumban before entering the temple of Dandayudhapani Swami.
Since then, pilgrims to Palani bring their offerings on their shoulders in a kavadi. The custom has spread from Palani to all Murugan temples around the world. Muruga, in His aspect as Lord Dandayudhapani, stands for renunciation
Thaipusam is without doubt the grandest and most awesome of Hindu festivals celebrated in Southeast Asia to honor Lord Subramaniam, son of Siva. Hundreds of Hindus who seek penance and absolution for past sins, or who wish to show gratitude to God for blessings during the year, vow to carry a kavadi-a wooden frame decorated with flowers and fruits and supported by long thin spikes pinned or driven into the carrier's body. To do so they go on a strict vegetarian diet for forty days prior to the festival.
Other devotees may have their tongues and cheeks pierced with spikes. Some spikes are more like long rods, ten or twelve feet long and as thick as a man's thumb. These are forced through his cheeks and he walks along holding the rod in his teeth, supported on both sides by his hands. Devotees insist their minds are on their gods and they do not feel pain. Nor do their wounds bleed. And, most unbelievable, there are no scars afterwards. The largest Thaipusam gathering is at Batu Caves north of Kulau Lumpur. Kavadi-carriers gather there before dawn, bathe in the river and enter a trance like religious euphoria before mounting the 272 steps to Lord Subramaniam's shrine within the gigantic caves. As many as 100,000 worshippers come to join in the solemn procession.
Inside the cave, a dozen white-clad priests tend to the thousands of worshippers and bestow upon them blessings and sacred ash. Spikes from their cheeks are removed, the kavadis are lifted, the trance subsides. A coconut is dashed to the ground and camphor is burned. The holy vow made to God has been fulfilled.
Hindus celebrate Thaipusam on the tenth month of their calendar. It coincides with the full moon at the end of January and beginning of February 'Thai' is the Hindu month which falls between January 15 to February 15 and 'Pusam' refers to a star which is at its brightest during the period of this festival. Celebrated in all parts of the world .
Thaipusam has come to mean the birthday of Lord Subramaniam, also known as lord Muruga, the younger son of Lord Shiva.
Leading up to the event, Hindus prepare themselves by fasting, praying and observing austerities.
Thaipusam festival is gradly celebrated in countries like
South India, Sri Lanka, Singapore, Malaysia, Fiji, Mauritious, Paris, South Africa, Seychelles, Toronto,,
Thailand ( not in a formal way though) The Thais celebrate Thaipusam in a horrifying way,so we cannot declare that as a proper Hindu festival.