DATU SALIBO, Philippines (NYTIMES) - The leader of the ISIS in the Philippines, Isnilon Hapilon, is dead. The city his forces seized, Marawi, on the island of Mindanao, is back in government hands after months of scorched-earth combat.

But the Islamic State in Iraq and Syria's (ISIS) influence in the Philippines is far from over, and communities on Mindanao are bracing for the next battles.

"I don't like to fight. But this is our land and we will not let them take this like they destroyed Marawi," said a veteran Christian militia fighter who goes by the nom de guerre Commander Ilangilang. (She named herself after the tree blossoms that bloom densely around her home town.) She says it is only a matter of time before the black flag of ISIS flutters in the mountainous periphery on the outskirts of Kauran, the farming community where she grew up and where she talked to the New York Times journalists recently, about 145km south of Marawi.

"That's why I have these," she said, gently tapping her .45-caliber pistol and a separate revolver, both holstered loosely around her thin waist.

The commander said she picked up her first gun when she was 13, in the early 1970s, and her family was embroiled in fighting Muslim separatist rebels in the area.

That separatist movement, and the sectarian and political resentment that drove it, never really went away. It evolved into Muslim militant groups that fought the government for decades, and in recent years proved to be fertile ground for the ISIS ideology and recruiters, as that Middle East-based movement sought to extend its influence around the globe.

That the old and resilient militant cells here are now being strengthened by the brand and resources of the group's international network has people worried all over Mindanao - including even some of the Muslim militants whose former comrades joined ISIS.

In a twist that would have been unimaginable even after they signed a peace deal with the Philippine government three years ago, members of the Moro Islamic Liberation Front, or MILF, are now leading their former enemies in the army against what some believe could become the next big ISIS uprising.

They are fighting in the forbidding marshlands of the town of Datu Salibo, about 210km drive south from Marawi.

Local Islamist groups claiming to represent ISIS have been trying to recruit the young with promises of cash and adventure, according to Commander Asiong. He is the self-appointed spokesman for the same Christian militia unit that Ilangilang belongs to: Red God's Army.

Asiong, 60, a former soldier turned community leader, said that even with the militants in Marawi defeated, ISIS' reach on Mindanao has spread. It has been aided by operatives in the Middle East who have posted well-produced videos of the so-called religious war, he said, and particularly by how the ISIS loyalists in Marawi managed to fight off the government for months.

His years of army service, spent fighting Muslim militants, have left him with deep scars in his neck and torso, and his left leg was all but cut away to save it after several bullets hit him there.

"They can regroup, join other IS allied groups here," he said, using the initials for ISIS. "While we have guns, our community is no match for them. So we pray that the government finishes them in Marawi. If not, there is nothing we can do except to protect ourselves and fight to the death. We will defend our land until troops arrive."

(On Monday, the Philippine defence secretary declared an end to the fighting in Marawi, saying that the "last group of stragglers" in the siege there had been killed.)

Asiong and Ilangilang spoke to journalists for The New York Times over goat meat stew in Asiong's hut. As we talked, the sound of explosions kept coming across the distance - mortar fire from an army camp targeting local rebels in a swampy region miles away.

On Christmas Day two years ago, a breakaway faction from the MILF called the Bangsamoro Islamic Freedom Fighters, or BIFF, attacked several areas, including Kauran, and killed 11 Christian farmers, Asiong said.

While BIFF says it is not officially affiliated with the ISIS loyalists who fought in Marawi, the local authorities think otherwise.

The rebel force has welcomed the Marawi offensive and has helped divert the army's attention by attacking nearby civilian communities. In June, as heavy fighting was going on in Marawi, BIFF militants briefly held more than 30 students in the remote town of Pigkawayan, about 80km south, forcing the military to spread its forces even more thinly.

A spokesman for the group, Abu Misry Mama, said in a brief telephone interview: "The fighting in Marawi is a good distraction. All I can say is, they do not belong to our group, which continues to fight for a separate homeland. But the enemy of my enemy is my friend." Another of those militant friends, a group that has explicitly pledged loyalty to ISIS, is fighting government and MILF forces in the marshlands near Datu Salibo.

The ISIS militants here are headed by the militant commander Abu Turaipe and are believed to number a few hundred. He was once allied with MILF, but broke away in protest over the peace deal with the government.

The swamp battle with the ISIS militants has been going on since August, but has gotten little press coverage, largely because the area is inaccessible and much of the attention has been focused on Marawi.

Von al Haq, the MILF's military commander, said that his fighters were "swimming while attacking, because the swamp waters are very deep". But the MILF and army alliance has slowly been winning, and in one offensive last month reported that it had recovered at least 20 improvised bombs and a number of black ISIS flags.

Nassrolah Gani, a 35-year-old police officer whose unit is helping the military in recovering casualties from the crocodile-infested marshland, said his men would be easily lost in the swamps were it not for their MILF guides.

Boots get sucked off by the mud, and thorny bushes are a natural impediment to moving faster. Their assault rifles often get wet, making them less reliable.

"It's an open mostly flat marshland, where you are open to sniper fire," Gani said. "When you enter the swamps, you've already dug your own grave." Gani said the latest intelligence data they received indicated that there were several Malaysian fighters who had joined Abu Turaipe's group.

Whether they had escaped from Marawi to this new front was hard to tell, but he believes their presence has bolstered the enemy force.

"We used to fight the MILF, but they are now fighting alongside us. So what is the bigger enemy? It is the Daesh-inspired groups," he added, using another name for ISIS.

Rommel Banlaoi, a security analyst who heads the Philippine Institute for Peace, Violence and Terrorism Research, says that other southern cities are at increased risk of attack by energised ISIS loyalists.

"They have won the battle strategically, as they have proven how long they can endure the fight against government forces," he said, adding that the Marawi battle will stand as an example of "martyrdom that can inspire others."

After the spectacle of the Marawi siege, more foreign fighters will be attuned to the fight on Mindanao, where past government efforts had aimed at ousting Muslims in favour of the Christian majority.

"Mindanao will continue to suffer the challenges of armed conflicts and violence because of many issues associated with the struggle of the people there for self-determination" being advocated by the Muslim forces, Banlaoi said. "It has simply become the new land of jihad."