They pray as they face Mount Kenya, which they believe to be the home of their God, known as Ngai.
And their name means "a united people."
But Kenya's Mungiki followers are no ordinary believers.
Their holy communion is tobacco-sniffing, their hairstyle that of the Mau Mau dreadlocks and the origin of the sect is still shrouded in mystery.
Since the late 1990s, the sect has left behind a trail of blood in its rejection of the trappings of Western culture.
Last week, the sect was back in the news following two days of clashes with police which left at least two policemen dead in Nairobi and 70 of its members in police custody.
The clashes were sparked by a dispute over the control of the private minibuses business in some parts of Nairobi, two weeks after 30 people were killed in similar clashes in the Rift Valley province.
Police say more than 50 people died last year in clashes involving the sect and owners of private minibuses, known as Matatu, in Nairobi alone.
"Mungiki is a politically motivated wing of a religious organisation," says Ken Ouko, a lecturer of sociology at the University of Nairobi.
"The religious bit is just a camouflage. It's more like an army unit. During the old system, they seemed to be complimentary to the system. In the new government, they seem to be antagonistic."
Inspired by the bloody Mau Mau rebellion of the 1950s against the British colonial rule, thousands of young Kenyans - mostly drawn from Kenya's largest tribe, the Kikuyu - flocked to the sect whose doctrines are based on traditional practices.
One theory has it that Mungiki was formed in 1988 with the aim of toppling the government of former President Daniel arap Moi. The sect was, at one time, associated with Mwakenya, an underground movement formed in 1979 to challenge the former Kanu regime.
Other reports say Mungiki was founded in 1987 by some young students in central Kenya to reclaim political power and wealth which its members claim was stolen from the Kikuyu.
Its leadership claims to have two million members around the country and to have infiltrated government offices, factories, schools and the armed forces - members who would not necessarily sport dreadlocks but support and finance the sect behind the scenes.
What is known is that the sect operate in secrecy, taking unusual oaths and saying strange prayers in forests and rivers in central Kenya.
Kikuyu oral literature portray gory images of their ritual scenes: Grown-up men with loincloths wrapped around them, standing bare foot in rivers, engaging in snuff sessions and bathing in blood mixed with urine and goat tripe.
One of its leaders, Maian Njenga, claims he had a vision from God (Ngai) commanding him to unite the Kikuyu and fight foreign ideologies. He is now in hiding, together with his co-leader Ndura Waruinge.
After last month's Mungiki attack in Nakuru, Interior Security Minister Chris Murungaru ordered a police crackdown on the sect. He accused the former ruling party Kanu of having nurtured and protected the sect during its reign.
But Kanu, now in the opposition, deny the allegations, saying leaders of the sect claim that some senior officials of the new government are members of the sect.
Away from the running battle with the police, the Mungiki members have also been involved in other anti-social acts:
Sociologist Ken Ouko says the Mungiki sect seem to have managed to address a social and spiritual hunger among the young slum dwellers which the church and the state have failed to feed:
"I would say this is a social reaction to either poverty or just being disgruntled.
"The best approach is talk to Mungiki. If we are going to hunt them down, the problem is going to be worse.
"We have to take a diplomatic approach."