There's a group of 7,500 soldiers who have been fighting an incalculably dangerous war for two years. They fight with weapons sometimes bigger than themselves. It is a war against a relentless enemy, no less gruesome and lawless and horrible than all of the others.

They are the YPJ (pronounced Yuh-Pah-Juh) or the Women's Protection Unit, an all-women, all-volunteer Kurdish military faction in Syria that formed in 2012 to defend the Kurdish population against the deadly attacks led by Syrian President Bashar al-Assad, the al-Nusra Front (an al-Qaeda affiliate), and ISIS.

In a recent BBC article, the YPJ, and their male counterpart unit, the YPG, were deemed to have been "extraordinarily successful" in a battle to squash the growing ISIS extremist group, despite limited means. It has been suggested the groups could be an effective ally to the West and just recently, both groups were credited with helping the U.S.-led effort to evacuate thousands of Yazidi refugees stranded on Mt. Sinjar after ISIS invaded their towns.

Photographer Erin Trieb recently spent a week documenting members of the YPJ at several military posts in Northeastern Syria and along the Syrian-Kurdish border. She recalled her time there, remembering the roof knocks of the explosions nearby: "One morning, I heard two loud blasts, one followed by another. I asked my translator, Rama, what it was and she said, 'That's just the YPJ and ISIS saying good morning to each other.'"

We asked Trieb to share with us her experience (and photographs) of the YPJ and the harrowing words these women fighters wanted the rest of the world to hear.

Evin Ahmed, 28. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

"We have to be free from the Syrian government," says YPJ member, Evin Ahmed, 28, (pictured above). "We need to control the area ourselves without depending on them. They can't protect us from [ISIS], we have to protect us [and] we defend everyone… no matter what race or religion they are."

Ahmed, like many of the YPJ, is fiercely loyal to her fellow-soldiers. She insists, "I love being a YPJ soldier, I love the other soldiers, we are closer than sisters. This is the only life for me. I can't imagine living any other way."

This sentiment, says Trieb, is echoed by all members of the YPJ, who live by a code of honesty, morals, and justice. "Their motto is 'Haval' or 'friendship'," explains Trieb, "and (it) is of utmost importance to them. They treat each other (and treated me) with a sense of solidarity and sisterhood. They address each other as Haval, and when they spoke to me, they would call me 'Haval Erin'. It enforces a constant sense of belonging and support."

Several of the women, like General Zelal, 33, (pictured below) one of the leaders of YPJ, expanded upon the idea of the independence the group brings women of the region: "I don't want to get married or have children or be in the house all day. I want to be free. If I couldn't be a YPJ I think my spirit would die. Being a YPJ soldier means being free—this is what it means to truly be free."

General Zelal, 33. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

"There is a sense among the women," says Trieb, "that the YPJ is in itself a feminist movement, even if it is not their main mission. They want 'equality' between women and men, and a part of why they joined was to develop and advance the perceptions about women in their culture—they can be strong and be leaders."

Sa-el Morad, 20, (pictured below), shared with Trieb that she enlisted in order to prove that, "we can do all the same things that men can do; that women can do everything; that there's nothing impossible for us.

"When I was at home, all the men just thought that the women are just cleaning the house and not going outside. But when I joined the YPJ everything changed. I showed all of them that I can hold a weapon, that I can fight in the clashes, that I can do everything that they thought was impossible for women. Now, the men back home changed their opinions about me and other women. Now they see that we are their equals, and that we have the same abilities, maybe sometimes more than them. They understand we are strong and that we can do everything they can."

Sa-el Morad, 20. Photographed at a YPJ training base near Derek City, Syria, Aug. 20, 2014.

According to Trieb, the women are indeed seen as just as strong, disciplined, and committed as their male counterparts. They endure many months and levels of rigorous training in weaponry and tactical maneuvers before they are even allowed to fight. They are also wholly celebrated by their community, which Trieb notes is unexpected in a part of the world where women are often seen as inferior to men.

To some in the region, they are seen as potentially more of a threat to ISIS than male soldiers. As Trieb recalls, "The saying among many Syrian Kurds is that ISIS is more terrified of being killed by women because if they are, they will not go to heaven."

Zevin Botan, 20. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

There is, despite the toughness of the YPJ, another unexpected side to the group that Trieb uncovered. "Though when training or on a mission they're very serious," she says, "in their downtime they're always joking around. The younger ones were a lot like American teenage girls and my time with them at the training post felt similar to summer camp—daily routine, lots of activities, and new recruits were getting to know one another."

YPJ solider, Narlene, 20. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

Trieb reveals that the YPJ are also very concerned with America's perception of them, "worrying that [Americans] think we're terrorists". The YPJ soldiers would ask Trieb 'What do they Americans think of us?'. "The truth is," says Trieb, "most of the West hasn't heard of the YPJ. It was really hard to have to tell them that. Because for them, they've been fighting this war every day for almost three years, so they were shocked to hear that most Americans don't know they exist."

It's difficult to say exactly why the force is largely unknown to Americans and many western nations. It could be in part due to the YPJ (and YPG) being closely linked to another Kurdish fighting force known as the Kurdistan Worker's Party or the PKK. The U.S. State Department, N.A.T.O., and the European Union have all designated the PKK a terrorist group, mainly due its violent, three-decade (1984-2013) struggle for autonomy from the Turkish State (a N.A.T.O. member). Although some have pointed out the success of the PKK in stopping ISIS, the tag still stands.

For now, the YPJ has no backing from western nations, relying mainly on its community to provide funding and supplies.

Avinar Kolcer, 26. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

Nonetheless, the women remain committed to the YPJ and its mission and are dedicated to protecting their people. They are not at all obligated to stay, says Trieb, and she believes all who join remain out of loyalty. None of them sign contracts. They can leave whenever they choose. Since the YPJ exists on a volunteer basis, many of the women are also unpaid. When supporters offer them payment in return for their service, "they will refuse the gift or donate it to the YPJ," Trieb notes.

Mizguin Ronahi. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

Evin Sadak, 20. Photographed at a YPJ training base near Derek City, Syria, Aug. 20, 2014.

The YPJ operates in two-week rotations on the front lines. Small groups are stationed at various observation posts all along the border of Rabia to keep the area secured, explains Trieb. They live in abandoned Iraqi army buildings, which, as one might imagine, are run down and lack any luxuries. Often, ISIS snipers are just 500 feet away, ready to shoot. Trieb, who made these photographs using the dilapidated building walls as backdrops, remembers having to duck and run between YPJ buildings to avoid being hit by enemy fire.

Sosen Shingel, 18. Photographed at a YPJ training base near Derek City, Syria, Aug. 20, 2014.

Shavin Bachouk, 26. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

Even under such intense conditions, the YPJ are always "staged and ready for conflict," Trieb says. She continues, "Some of them had their own personal cars parked outside the building so that they could quite literally 'drive' into conflict, should it erupt. They are fearless," says Trieb, "though they might not say they are. They consider fear and then they go forward anyway."

Hasrat Sahad, 23. Photographed at a YPJ checkpoint-base, on the outskirts of Rabia, Kurdistan, on Aug. 7, 2014.

Editor's NOTE: In recent weeks, the YPJ has come under increased attack. Several of the women photographed by Trieb have been injured and some have been captured by ISIS.

Originally published on .

Elizabeth Griffin Strategic Visual Content Editor for Hearst Digital Media, Photo Editor of Esquire.com, and staff photographer at Hearst.

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