Rahman Roslan / Getty Images A member of the Malaysian Special Forces Unit stands guard as a standoff continues between the Malaysian police and an armed group of Filipinos in Kampung Senallang Lama, Malaysia, March 13, 2013.

The Sultan of Sulu’s Manila home lies in a poor Muslim neighborhood in the south of the Philippine capital. Its high walls are festooned with royal banners weighted down by repurposed plastic soda bottles. Advertisements for “Septic Tank Plumbing Services” are posted next to a derelict Opel station wagon, now the only fixture on the sidewalk out front. In early February, when armed supporters of Sultan Jamalul Kiram III landed in Malaysian Borneo to enforce an ancestral-land claim, media flocked here to meet the low-profile leader, whose forebears once held sway over the Sulu Archipelago in the southern Philippines. (These days, there is no civil power attached to the role.) TV news crews crowded the sidewalk around-the-clock as, hundreds of kilometers away, the sultan’s men were locked in a clash with Malaysian security forces that has since killed over 70 people and displaced scores.

(MORE: Malaysia: At Least 26 Dead as Police Raid Sabah Siege)

Today, the street outside the sultan’s crumbling residence is quieter, but the fallout from his brazen campaign has not settled. As Malaysian security forces continue their mopping up operations against the sultan’s men in eastern Sabah province, a fresh wave of fighters has reportedly entered the fray. According to Abraham Idjirani, spokesman for the Royal Sultanate of Sulu and North Borneo, some 400 armed men have managed to breach a joint Malaysian-Filipino naval blockade in the Sulu Sea. It’s not yet clear who sent them, though the sultanate asserts they are from Mindanao, where leaders of the southern Philippine militant group Moro National Liberation Front (MNLF) have pledged support. On March 31, the MNLF threatened a “long, protracted war” if Malaysian forces continued their pursuit of the self-proclaimed Royal Army of Sulu.

The Sabah affair is emblematic of territorial disputes that have long overshadowed the region. Centuries before the modern states of Malaysia and the Philippines came into being, the islands of the Sulu Sea, and part of resource-rich Sabah, were ruled by the Sultanate of Sulu. In 1878, the sultan made a fateful deal to lease Sabah to a British commercial interest; the territory was later annexed by the British crown and, in 1963, became part of an independent Malaysia. Now the Kiram family wants it back. It still receives roughly $1,700 a year in rent from Kuala Lumpur, but views the sum as ridiculous given how profitable the land is and the status afforded to other sultans in Malaysia. (For reference, Sultan Kiram and the Sultan of Brunei, once named the world’s richest man, share the same great-great grandfather.)

These days, Sultan Kiram, 74, could use some extra cash. On a recent morning, he was away at the hospital for one of his biweekly dialysis sessions. Fatima, his panguian — to use the term bestowed on a sultan’s wife — insists that while “he’s still O.K.,” he’s not the fleet-footed tango dancer who dazzled her early in their marriage. A retired civil servant, she worked full-time for over 20 years to support the family while the sultan managed a modest seafood-exporting business. In between filling cuttlefish orders from Japan, he was called upon to help mediate domestic insurgencies. Photo albums on the coffee table show the sultan wearing his trademark brown sunglasses next to grim-faced MNLF rebels and government officers.

(MORE: Sabah Standoff: Diplomatic Drama After Filipino Militants Storm Malaysia)

Back in the 1970s, Fatima recalls urging her husband to also take up the gun. “I told him, ‘Why don’t you go the mountains and fight the [Malaysians]’ … you are only recognized if you are a rebel force,” she says. For years, the sultan countered that patience and diplomacy were the best course and wrote letters to officials, but to no avail. On Feb. 6, about 200 of his followers — some of them heavily armed — were dispatched to Sabah. A weeks-long impasse in a coastal village ended in bloodshed, as a Malaysian ground assault gave way to air strikes. The Sultan’s fighters and their commander, Agbimuddin Kiram, the sultan’s 70-year-old brother, melted into the jungle, where sporadic gun battles persist.

The crackdown has made a hard life even harder for the 800,000–plus Filipino migrant workers who help sustain Sabah’s booming palm-oil and petroleum industries. The Malaysian government, already facing criticism for harsh treatment of its migrant underclass, is accused by rights groups of widespread harassment of civilians as it moves to flush out the Royal Army. Dozens of homes have been destroyed and hundreds of Filipinos have fled abroad. Analysts warn that the toll will further aggravate anti-Malaysian sentiment in the southern Philippines, less than an hour away by boat.

With such valuable interests in the region and general elections on the horizon, the Malaysian government has shown no willingness to cede any ground. State officials, keen to project strength, have labeled the Royal Army “terrorists” and ignored the U.N.’s demands for a cease-fire. In Manila, President Benigno Aquino has tried to balance relations with Malaysia, a key ally and trading partner, with pressing political calculations at home as a midterm ballot nears. The sultan enjoys considerable standing among Muslims in the restive south of the country, and his claim to Sabah has become a matter of local pride.

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Sultan Kiram judges the incursion to be a partial success in that his cause finally has the world’s attention. “I regret that people have died,” he says, moments after returning from his hospital treatment, walking with a cane. “However, we must make a sacrifice to enjoy the fruits that are rightfully ours.” He would not (or could not) say who the new fighters who have joined his army were, only that they were “volunteers” going to Sabah to seek “revenge for their brothers” killed by Malaysian forces. “We cannot stop people now,” he adds, somewhat cryptically, “but peace is our hope.”

The sultan says his people will hold out as long as it takes, but time may not be on his side. At midday his voice was faint and, behind the signature dark glasses, one of his eyes was fully shut. A handful of local journalists who by now had gathered outside to interview him would have to wait a while longer. The sultan needed a nap.