Karim, an Iraqi I know who belongs to the Yazidi minority, had to flee his home town near Mt. Sinjar when the Islamic State in Iraq and al-Sham (ISIS) overran it, in August. (I wrote about him then; Karim is a pseudonym.) He and his family barely escaped with their lives, and almost nothing else, to the Iraqi Kurdish city of Dohuk. Several times since then, Karim has told me that he planned to return home at the earliest possible opportunity. In the middle of September, he and his father, who is around sixty, left their family and retraced their escape route in reverse, driving through Syrian territory held by Kurdish rebels, who are allies of the Yazidis, down to the Iraqi border. From there, they crossed into Iraq, around twenty miles from the town of Sinjar, and joined a small group of Yazidi volunteers who have formed an armed resistance to ISIS. The group’s base is the town of Sharfadin, situated on the plains below the mountain, where there is a Yazidi shrine.

The Yazidi resistance, led by a politician in his sixties named Qasim Shasho, has received very little attention outside Iraq. One account, on Medium, describes the group as being made up of just a couple thousand fighters. Few of them have any military training—Karim has never fired a shot at another human being. They are outnumbered and outgunned, with AK-47s, rocket-propelled grenade launchers, and a few fifty-calibre guns against ISIS’s artillery and armored vehicles. The Yazidis are capable of hit-and-run ambushes, but they haven’t been able to take and hold territory. Many of their relatives who are now refugees in Kurdistan have abandoned the idea of ever returning to their ancient home.

Around the beginning of this month, ISIS seized the road through Syria to Dohuk, cutting off Karim’s land route back to safety. His father was having heart trouble, and a few days ago the two of them travelled up Mt. Sinjar, a steep and rugged area, holy to Yazidis, that became their sanctuary and their grave when ISIS attacked the towns around it, two months ago. From the top of the mountain, Karim’s father was evacuated to Dohuk on one of the Iraqi Air Force helicopters that make regular flights back and forth, carrying fighters and weapons to the mountain and ailing and elderly refugees to Kurdistan.

Yesterday, I spoke on the phone with Karim. He’s still at the top of Mt. Sinjar, living in a military camp with around a hundred fighters, the majority of them Kurdish, the rest Yazidis. They sleep in United Nations tents and eat canned food brought in by humanitarian airdrops. There is no real way out except by airlift—in the past ten or twelve days, according to Karim, ISIS has pushed Yazidi fighters out of villages north and west of Mt. Sinjar, and they now surround the mountain. Karim told me that there are still about a thousand civilians around the mountain, also living in tents. The humanitarian airdrops are not enough, food is running low, and the past few nights have been cold with the approach of winter. The Yazidi resistance fighters want an international ground force to liberate Sinjar—something that they are unlikely to get.

A few hours before we spoke, Karim said, five Yazidi girls arrived at the mountaintop camp. The youngest was nine, the oldest twenty. They had walked several dozen miles from their town to the south of the mountain. They carried nothing with them and were barefoot. The girls said that they had been held prisoner for weeks by ISIS fighters, and were badly beaten, according to Karim. Other Yazidi girls and women have been distributed in slave markets to ISIS fighters, and when I asked Karim if the girls had also been raped, he told me, “I couldn’t bear to ask that question, to be honest.” The girls had been held in houses, not a prison, and they’d managed to escape through the back door and make contact by phone with people on the mountain. “They were quiet, not crying—even the little girls, they weren’t crying,” Karim said. “It looks like this was the first time they see a human being.”

After talking with the girls, Karim found himself unable to eat his lunch. “I don’t know. I think I’m helping people here,” he said. “I feel good sometimes—but those girls are making me heartbroken. Imagine—I don’t know their names, I don’t know where they’re from—imagine how their father or brother or someone in their family feels.”

Karim returned from safety to Mt. Sinjar, and he is now risking his life, primarily for his home and his people. The Yazidis are a tiny, beleaguered, resilient minority in a hostile land, and a history of oppression has made them insular. Karim doesn’t trust the Kurdish peshmerga fighters in the military camp—who are risking their lives at his side—enough to let me identify him. “People here are from different places,” he said. “People you don’t know, you can’t trust.” Karim feels that Yazidis have been singled out by ISIS—a group that has slaughtered hundreds of Iraqi and Syrian Shiite prisoners of war, beheaded American and British hostages, driven out Mosul’s ancient Christian population, and is now threatening to wipe out a Kurdish city on the Syrian-Turkish border—for uniquely terrible treatment. And yet the first time we spoke, in July, and again yesterday, Karim told me that ISIS is a plague on all humanity. Everything the world has seen since my first conversation with him has proved Karim right.

In that sense, while his motives might be parochial, Karim is also fighting for you and me. So are the fighters of the Syrian Kurdish People’s Protection Units, or Y.P.G., among them many women, who have been holding onto the border city of Kobani for weeks against a heavy ISIS offensive, and who now face defeat and, perhaps, annihilation. (The Y.P.G. were instrumental in the rescue of Yazidis in August, though Karim told me that, at the moment, the tragedy of Kobani feels far away from Mt. Sinjar: “Injured people, they talk about their injury.”) Staffan de Mistura, the U.N. special envoy for Syria, has warned against a Bosnia-style massacre in Kobani. “Do you remember Srebrenica?” he asked, at a news conference last week. “We do. We never forgot, and probably we never forgave ourselves.” U.S. air strikes have done little to weaken ISIS—we have been playing catch-up for the past two months—and now that the Islamists are in the city, and the fighting is street to street, it might be too late. Meanwhile, Turkey has refused to allow Kurdish volunteers to cross the border fence and help in the defense of the city. Apparently, President Recep Tayyip Erdoğan, trying to get the upper hand in negotiations with Turkey’s own separatist Kurdish Workers’ Party, would rather see another Srebrenica than give any tactical advantage to another Kurdish group. In this instance, Turkey, despite its stated opposition to ISIS, is serving as a de-facto ally of the group.

An elderly refugee from Kobani, quoted in the Guardian, echoed what Karim told me. “They destroy our homes, they rape our girls,” he said of ISIS. “We are defending the whole world from this terror.” At the very least, the rest of us owe the Yazidis of Sinjar and the Kurds of Kobani the chance to save themselves.