The backstory is baffling. But whatever the myth or legend behind of the Nine Emperor Gods festival, there's no doubting the fervor with which devotees here in Malaysia mark this Taoist celebration.

It all begins on the eve of the ninth lunar month, and comes to a climax on the ninth night, with many devotees who have cleansed themselves with a vegetarian diet since the start of the ninth month walking across a causeway of hot coals.

Throughout the nine days of the festival, worshipers flock to the Kau Ong Yah temple – one of a handful here in Malaysia that are considered “Nine Emperor God temples.” They light incense, make food offerings, get blessings, pray. Many don white robes, which are said to symbolize mourning for the Nine Emperor Gods.

But who were the Nine Emperor Gods? One popular version is that they were righteous men who sought to overthrow China's Qing Dynasty (1644-1912) and gave their lives to the cause. After their death, the imperial court conferred on their spirits the status of gods. Other versions have them as sort of Chinese Robin Hoods, stealing from the rich to give to the poor.

Whatever legend they believe, the worshipers attribute to the gods and the power to bring prosperity, as well as ensure good health.

This temple is now a grand, multi-structure complex with twin pagodas and much ornate decoration, but it didn't start out that way.

“From what my grandmother told me, it just started out as a sort of shack,” said Wong Soon Kiat, a volunteer who helps tidy up the steady stream of exhausted joss sticks. “Worshipers came here to pray and when their wishes were granted, they returned and donated money which helped to build this temple.”

The worship of the Nine Emperor Gods has its origins in the Fujian and Guangdong Provinces in southern China and migrants from there brought the practice to Southeast Asia. But it seems that celebration of this festival is largely confined now to Malaysia, Thailand, Singapore and Myanmar. In Thailand, I have seen images of the celebrations there, which feature people piercing their faces with a bizarre array of objects including broom handles and lamp stands and bicycle frames.

Nothing so gruesome happens here in Malaysia, with the firewalking as extreme as it gets. Apparently Singapore found it too extreme and banned the firewalking on safety grounds back in 1978.

Teams of devotees empty sack after sack of charcoal onto a sand-covered courtyard in front of the temple entrance. It takes a couple of hours to pile it up, tamp it down, shape it the way they want it. Hundreds of incense sticks and offerings of golden paper are placed into or on top of the charcoal mound, which is then doused with copious amounts of petrol before being set alight.

Cho Hock Heng has been firewalking for the past decade. He said observing a strict vegetarian diet in the run-up to the ritual helps to cleanse the body and prepare the devotees.

“Doing the firewalking brings good fortune and helps to protect our families and keep them safe no matter where they travel,” he said.

Aside from the worshippers, many curious people come to witness the ritual. While professional photographers and cameraman are allowed within the fenced-off compound, onlookers are kept back.

Spirit mediums accompanied by musicians circle the compound stopping at shrines at the four corners. Then teams of men carrying ornate, gilded sedan chairs containing statues of the gods enter. They rock violently back and forth, side to side, in what is said to be a sign that a divine force is present.

Then the moment of truth or dare. The worshippers carry the sedans across the causeway of hot coals followed by a steady stream of people in white robes carrying smaller offerings.

The procession goes on for hours.

I spotted one obviously foreign couple taking in the spectacle. They were retirees from the Netherlands who have made Malaysia their second home.

“It was amazing,” said Bert Beekes.

“We came last Wednesday for the first time, and everyone told us we had to come back on this Wednesday for the people walking on the fire,” Marianne Beekes said. “It was very special. I don't think I'd like to do it.”

But there was no shortage of devotees keen to take part in the firey cleansing ritual, as their ancestors had done for generations before them.

And judging by the age spread of those taking part, from 20-somethings to the elderly, there's no danger of this festival - or its dramatic climax - dying out any time soon.