Kobane suffered such destruction in the Kurdish fight against Isis that rebuilding will be an onerous task

Buildings lie in waste, reduced to rubble. Others, their faces are shorn clean off. Bullet casings litter the streets, unexploded mortars burrow into pavements.

The charred body of an Isis (Islamic State) fighter lies beside an outhouse on the eastern front, a grimace scored into his face, fingers frozen, tearing at the sky.

For months, outgunned fighters fended off Isis jihadists in the city of Kobane, one of three Kurdish cantons in Syria's north.

Last week, they drove the extremists into the countryside, prompting celebrations by the 30 million Kurds scattered across Iran, Iraq, Syria and Turkey.

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Yet the devastation that Isis left in its wake is massive. And, given the limited strategic value of the city, the destruction carries a poignant senselessness.

"In any case, even if the Kurds have taken back Kobane, this city is all rotten now," says a 19-year-old Isis militant who fought, and was injured, in Kobane, reached in Raqqa via Skype. "They can't rebuild. It is all broken. It is emptiness."

Kobane became a graveyard for Isis. "Normally, if you go to Kobane, you will be dead within 10 days," says the Isis fighter.

Bodies lie in gutters aside piles of rubble. Many more are expected to be discovered as the ruins are cleared.

"The first step will be to generate electricity, provide running water and to clear the streets," says Mohammed Sady, a municipal worker standing amid the ruin of central Kobane, tasked with overseeing the rebuild.

"Then we need to retrieve bodies from beneath the rubble."

The four-month Isis siege was brutal. Its attacks began with shelling and suicide car-bombs. Then, says Ismat Sheik Hassan, the canton's defence minister, the "fighters would come".

The city's Kurdish defenders held out with a ring of snipers. Others blasted rocket-propelled grenades into car-bombs. Small teams ambushed the extremists in the night, making off with weapons and communications equipment, monitoring the extremists' conversations.

Yet, Kobane is vulnerable, isolated from Syria's other Kurdish cantons. As Isis squeezed the Kurds into an ever-shrinking corner of the city, the US launched a campaign of airstrikes.

That intervention, buttressed by a deployment of fighters from Iraqi Kurdistan, known as the Peshmerga, likely spared the city from the Islamists. The US-led coalition launched some 700 airstrikes, a blitzkrieg that turned the tide.

"The whole world saw how we resisted Daash," says Hassan, using the common Arabic acronym for Isis, standing amid Kobane's central city ruins. "But the airstrikes saved us."

A short walk away, a decomposing body shrinks in a pile of clothes. Strands of the extremists' matted beard are stuck to his chest.

Most of the flesh of the Isis fighter's head, about a metre away, has putrefied, exposing a single gold tooth. A wound on the left temple marks a bullet's entry point. The back of the head is caved in.

He appears to have been shot at close range and subsequently decapitated.

Along a street once bustling with markets, piles of rubble and steel stretch up contorted. Burned out cars sit upended. Others are crushed beneath collapsed buildings.

"We need to rebuild the city," says Anwer Muslim, the city leader. "But we may have to build Kobane somewhere else instead."

Explosions rumble. Isis is using tanks to shell the city, from its positions around 8km away. US warplanes howl high above.

Bullet-riddled cars careen down streets, Kurdish flags fluttering from windows as fighters celebrate.

"I saw Isis so many times, battling them house-to-house and on the eastern front," says Rokan, a female fighter with the Peoples' Protection Units, or YPG, patrolling a deserted area of the city, much of it in ruin. The group is the armed wing of the Democratic Union Party (PYD), which administers Syria's Kurdish areas. Its fighters led the defence of Kobane. "They bought heavy weapons and shelled us constantly, but we never broke ranks." Now she is tasked with stopping civilians from entering the area: "there are a lot" of unexploded mines, she says.

The defence of Kobane did much to boost street-level hopes of a newfound Kurdish unity. Yet analysts caution against optimism: the region's Kurds are deeply divided. The battle for Kobane drew three major Kurdish factions from the region. But other ultra-conservative Kurds, notably from Halajba in northern Iraq and Afrin north of Aleppo, joined Isis in the assault.

"We came to protect the Kurdish revolution in Syria," says a fighter from the Kurdistan Workers' Party (PKK), an insurgent group from Turkey that has battled the Turkish state for three decades. The man, sitting beside a wood burner, could not be named for security reasons. "We will not accept the Arab fascists and fighters from all over the world attacking Kurdish lands."

In the yard with the charred, grimacing Isis fighter - his eyes still wide - the rain comes down harder. His clawed fingers drip water. The surrounding ground is tainted in a blackened silhouette. "My neighbour called me. He said there was a dead Isis man on my property," says Mahmoud Hasan, who owns the house and was reached by cellphone in Turkey. "I asked him to get rid of the body. So he took burner oil (accelerant) and set him on fire."

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