Marijan is not alone in his disapproval. Some in Yogyakarta accuse Hamengku Buwono X of turning this cultural capital into a city of shopping malls and of spending too much time on the golf course. They yearn for the comfort of ancient rites and criticize the sultan for neglecting ceremonies his father routinely attended. In 2006, the sultan was conspicuously absent from an annual ritual to bless offerings for the ogre Sapu Jagat and the sea goddess Ratu Kidul. The offerings—which include food, flowers, cloth, and clippings of the sultan's hair and fingernails—are meant to ensure the sacred alignment between the volcano, his palace, and the Indian Ocean, and thus the safety of the people.

Less than two weeks after Merapi's first major eruption of 2006, a powerful earthquake had struck south of Yogyakarta, killing more than 5,000 people. The palace and royal burial grounds were also badly damaged—an ill omen for the sultan, already the target of public outrage over the slow distribution of relief funds. Damage control was in order. Even a modern sultan can't escape the force of the old beliefs. With or without him, the annual ritual offerings had to be made.

So the sultan's staff laid out offerings in the quake-damaged courtyard for a brief ceremony, then sent them to waiting cars, which sped off in two separate directions. The first set of offerings was brought to Marijan's house. The next morning, the Gatekeeper hiked to a pavilion a mile from the volcano's peak where, amid trees snapped in half by the latest pyroclastic flow and the crash of tumbling boulders, he solemnly prayed over the sultan's offerings.

A second set of offerings was driven south to Parangkusumo, the Indian Ocean beach where, legend says, the sultan's 16th-century ancestor Senopati met the sea goddess Ratu Kidul. Thousands of houses lay in rubble amid the rice fields. At Parangkusumo, the sultan's staff buried his hair and fingernail clippings near the beach, in a walled-off compound where two flower-strewn stones marked the site of the ancient encounter. Other offerings were flung into the waves.

It is August. Three months have elapsed since the first major eruption of the year. Though still active, Merapi has settled down. Residents attribute the calm to Marijan's prayers and presence on the volcano. But calm in Indonesia is about as long lasting as a plume of smoke.

THE ANTAGONIST in the equation is militant Islam. Radicalized by events such as 9/11 and the United States invasion of Iraq, groups preaching a more austere version of Islam have gained strength and influence, fueled by the perception that Islam is the cure for Indonesia's ills, notably its poverty and corruption. Some local governments have introduced measures based on sharia, Islamic law, that call for the arrest of women not wearing head scarves or the public whipping of adulterous couples.

Militant Islamists have targeted mysticism in the conviction that such practices pollute the faith. Islamic relief workers who arrived in Yogyakarta following Merapi's first blowup in May 2006 vowed to disrupt rituals held on the volcano, while in Jakarta members of an Islamic youth group hacked branches from a sacred banyan tree to prove it had no magical power.