As Salafis arrive to seek final battle with Shias, one town elder claims: 'They will demand that we return to the seventh century'

In early summer, Abu Ismael, a six-year veteran of al-Qaida, left the insurgency still blazing in his homeland of Iraq and travelled to what he believes is the start of the apocalypse.

He secured cash from a benefactor in the northern Iraqi city of Erbil, then approached a weapons dealer in Anbar province, a desolate corner of the country that was not long ago a staging point for jihadis arriving from Syria and is now a gateway for those going the other way.

"It was easy," he said, in the sitting room of a house in the Syrian city of Aleppo. "The money was no problem, neither was the weapon, or the motivation. This will be a fight against the great enemy."

Around the hard-bitten 23-year-old sat three members of a Syrian rebel militia who were acting as his hosts. They looked at the floor as the young jihadi explained Qur'anic teachings that he said were shaping the battle ahead. "I don't care about the future," he said. "I care about today. Muhammad the Messenger said there would be a battle between the Persians and the Sunnis. And it is coming.

"When the regime falls, all those who fought against the Muslims will be my enemy, especially the Shias," he said, reiterating a view held by some Sunni extremists that Shia are their biggest foes.

The hosts shifted nervously, still avoiding eye contact. The stranger in their midst had sought refuge among them two months ago. Since then he had rented a house, won a ride to the battle zone whenever he wants and earned the support of some of the area's rebel units.

He has even won a more coveted prize: the right to marry the daughter of one of the fighter's cousins, a union that took place on Thursday with the qualified blessing of residents and clerics.

Not everyone in the unit was happy with the wedding. "It's you scratch my back, I scratch yours," said one young rebel, Abu Saif. "He's a Salafi, there is no doubt about that," he added, referring to the ultra-fundamentalist school of Qur'anic thinking. "And he doesn't represent what we believe."

Remonstrating with the unnamed young girl's uncle sitting nearby, Abu Saif said: "You tell me what benefit we get from him, or that your family gets." The uncle shrugged, offering no reply.

As Syria's civil war grinds inexorably on, it is becoming as much a clash of ideologies as a battle of military will. The frontlines that were hurriedly carved out of Aleppo's ancient stone heart and concrete suburbs during the heady days of summer now seem almost secondary in the contest to determine the type of society that will one day rise from the ruins.

For the most part, the opposition movement is staying true to the ethos that led many of the country's towns and citizens to mount a challenge to President Bashar al-Assad's absolute state control over their lives. But around the fringes, there are signs that the revolution's original values are starting to fray. The narrative of a defiant street versus a draconian state, so simple in March 2011, is now far more complicated.

"We want just what they got in Tunis and Egypt," said Mahmoud Razak, a shop-keeper in the outer suburbs. "Freedom and the chance to progress in life. But we thought it would take 19 days like it took [in Egypt]. It's now 19 months. We didn't know it would be this difficult."

To those now hosting Abu Ismael, the Iraqi jihadi embodies one of the major problems. Though for the most part conservative and pious, the men of this part of Aleppo refuse to see the crisis now consuming Syria in existential terms. To them, this is still a fight for self-determination, not the forum for an apocalyptic showdown with a preordained foe.

"What is this global jihad that he talks about?" asked a town elder, Abu Abdullah, after the Iraqi had left to prepare for his wedding. "We will be used as toys by them, just as the Sunni communities were in Iraq. When they have had their way with us they will demand that we return to the seventh century under the blade of a sword."

Abu Ismael made no secret of his wish for Syria to be the heartland of an al-Qaida-led renaissance. Nor, unusually, did he hide what he had done in Iraq, or what he planned to do in the new war. In a candid hour-long discussion, he offered a rare insight into the terror group's designs on Syria and the organisation's fraught battle to assert itself. "I was a member of the al-Qaida organisation from 2005-11," he said, his black eyes set in an unflinching stare. "I joined them with my father when I was 16 and apart from one and a half months in prison, I was very active in every way."

The young Iraqi's attire and demeanour were unmistakably those of a Salafi. He refused cigarettes, cuffed the bottoms of his fatigues at ankle level and wore a black skull cap over closely cropped black hair. More instructively, he spoke with derision about Shia Muslims, whom he said were increasingly travelling to Syria to fight the Sunni-led opposition.

"They are saying they are going to protect the Sit Zeinab mosque in Damascus," he said of a shrine revered by Shias. "The Jaish al-Mahdi [Mahdi army] and Hezbollah are just using that as cover to enter the rest of Syria. We will not let them. We will attack it, perhaps not to destroy it, but to drive them out.

"There are around 50 Iraqis in each area of northern Syria. Perhaps more. It was not difficult to get here and it is not hard to find other mujahideen. We can fight where we want to and when we want to. And God willing we will prevail."

His restless hosts were not so sure. Bound by social customs that offer wayfarers shelter and hospitality, this rebel unit seemed to sense that trouble is brewing between them and the growing band of global jihadis. Many rebel groups the Guardian spoke to this week said a showdown was looming with the new arrivals.

"I give it six months," said one rebel officer at a checkpoint in the old market place in the central Aleppo suburb of Midan on Thursday. "Maybe a year," said another. "I was in Iraq fighting the Americans and I saw how they changed once they sensed they had power."

"It's so mixed up," said a third young rebel, a defector from Damascus. "And this is just how Bashar wants it."

Rise of the Salafis

Bashar al-Assad has insisted from the start that Syria was facing attack by "armed terrorist gangs", not a popular uprising – though there is ample evidence of the army firing on mostly unarmed demonstrators. But it has become clear that extremist Salafi or jihadi groups, some linked to al-Qaida, are now a significant element of the armed opposition.

Alongside fighters from al-Qaida in Iraq or Fatah al-Islam from Lebanon is the mysterious Jabhat al-Nusra, which has claimed responsibility for suicide bombings in Damascus and Aleppo. It is sympathetic to al-Qaida. Others hail from Jordan, Libya and Algeria.

The overwhelming majority of jihadis are Syrian, with the number of foreigners ranging from 1,200 to 1,500 members. Jihadi groups in Syria represent less than 10% of all fighters. Still, many have combat experience in Iraq, Afghanistan, Yemen, and Libya and compete for funds and weapons with the Free Syrian Army, the main armed opposition group.

"Most foreign fighters go abroad to defend their fellow Muslim brethren from being slaughtered," according to Aaron Y Zelin, an analyst at the Washington Institute.

"Once in the area of battle, though, many come into closer contact with hardline jihadis, as well as fighters from other countries, and are exposed to new ideas.

"Therefore, portions of foreign fighters are not fighting to help establish a future state for Syrian nationals. Rather, they hope to annex it to be part of their grander aims of establishing emirates that will eventually lead to a re-established caliphate – however fanciful this project might be." Ian Black