Their numbers are small, their weapons home-made – but for more than two years they have tackled IS with no help from the West.
Right now in Syria a desperate fight is under way against Islamic State (IS) forces that control so much of the north of the country.
In the east that fight is being carried out virtually unseen to the rest of the world by People’s Protection Units (YPG) fighters, Syrian Kurds, who are doing so with almost no assistance.
They have been fighting IS for longer than any other group.
With home-made weapons and armoured cars and some old heavy guns, they fight in dusty villages, the countryside and larger towns to try and force IS back to the west of Syria.
Kobani has been surrounded for weeks by IS but there are many other towns that are under siege. From Sari Kani 100 miles or so east of Kobani the YPG have been taking back ground from IS.
They would dearly love to reach their colleagues in Kobani but, with no assistance, even they accept it will be an almost impossible mission.
Always moving and repositioning themselves, the front line is a confused and confusing battle of attrition.
The men of the YPG and the women fighters of the Women’s Protection Unit (YPJ) work together. There is no battlefield difference between the sexes. They all throw themselves into the fight. They are protecting their homeland and say to us that they can die at the front or at home, but either way they are prepared to die.
Against the odds and the better equipped IS forces, they have made ground and captured weapons. In a rear position they work on tanks captured from IS and they showed us the bodies of 20 IS jihadists they killed in a night operation.
We travelled from Iraq through Syria. The birthplace of IS is one of the most dangerous places on earth today. The YPG grip is tenuous and the vast open spaces are difficult to protect from IS incursions.
These Syrian Kurds are hemmed in. The Turkish border lies to the north and its military considers the YPG a terrorist organisation.
To the south, east and west IS controls all the land leading to Iraq and across its border.
On the newest YPG front lines we came across a seemingly rag-tag group of fighters. But while they may look so they are in fact well trained and utterly determined.
A hill-top cemetery has become a fort. They watch across the plains and the villages that IS control. They are so close they can hear the foreign languages of the IS fighters on their walkie-talkies.
But nobody here seems in any way frightened of IS. They laugh and joke and prepare to fight. Day in, day out.
The YPG are very canny. Their front-line positions are never static for long. Their numbers are small so they move positions and manoeuvre around the battlefield looking for signs of IS weakness. Then they attack. Both sides are doing this but one gets the sense that the Kurds are more determined.
While IS have many foreign fighters the YPG also have a small contingent. Chechens, Europeans and Americans who have decided to help fight IS.
Brian Wilson is from Ohio. A divorcee with two children, this veteran of the first Gulf War and 16 years a police sheriff in the United States decided to come here a month ago and join the fight. He was shocked that the West was doing nothing to help here.
“They have been holding out against DASH (IS) in this area for going on two, two and a half years,” he told me on the front line.
“They are outgunned. They are brave fighters. They just need more help. If they had better technology, better weapons, they could finish IS on their own. More airstrikes would be very helpful to clear out some areas.”
The YPG are fighting multiple fronts on a constant basis. Sometimes they are in cities and towns, sometimes in open countryside. But they are holding on and sometimes doing better than that.
And, as they say, they will do that to the death if necessary.