Who is who in northern Syria?

Syrian regime

Led by Bashar al Assad, the Syrian regime has been fighting against opposition groups since the Arab uprising made its way to Syria in 2011.

The regime first withdrew from the areas that the YPG claimed in northern Syria. Later, Assad released many Daesh militants from prison. And in 2014, Daesh took control of some parts of the north of the country. That move changed the stance of the international community towards the civil war, making the defeat of Daesh the biggest priority, instead of the regime.

Meanwhile, the regime itself was losing ground against the opposition groups. After Russia actively became involved in the war lending support to the regime with its air force in 2015, the regime gained an upper hand. Assad has reclaimed nearly half of the country since then, including Aleppo in the north.

Since then, the regime aimed to move towards Idlib, in the country's northwest. Regime forces backed by Russia and Iran have escalated their offensives there.

Free Syrian Army (FSA)

When the Assad regime violently responded to Syria's peaceful protests in 2011, opposition groups took up arms and began forming moderate opposition groups under the umbrella of the Free Syrian Army (FSA). They were backed, trained and armed by the US, Turkey and Gulf countries in the first years of civil war. But since Daesh became a priority, the US and the Gulf countries cut their support for the FSA. The group aims to remove Assad from office as he is held responsible for the deaths of near a million Syrians and displacing about 10 million others. Turkey is the only country who continues its full support for the group.

Since it includes dozens of different groups that are not united under one command, the FSA has factionalisation problems.

In the north, it was defeated by Daesh in 2013 and 2014, but couldn't go back after Daesh was finally defeated, because the YPG now holds control of the territory and doesn't let any other groups into the areas it controls. 

The FSA groups are now only active in Afrin, Idlib and the Euphrates Shield area in northern Syria.

Turkey's first cross-border military operation in Syria, the Operation Euphrates Shield, was performed by FSA groups along with Turkish troops.

In Afrin as well, they are taking part in Turkey's Operation Olive Branch. 

And in Idlib, they are fighting both the regime forces and al Qaeda-affiliated Hayat Tahrir al Sham.

Syrian National Army

The National Army is a new army composed of 36 different opposition groups under the umbrella of the FSA.

It was officially formed on December 30 with the aim of training and uniting the various FSA groups under one command, which is meant to help the FSA transition to a regular, professional army in the future of Syria.

The National Army, which includes about 10,000 troops, is currently taking part in Turkey's ongoing Operation Olive Branch in the northern Syrian city of Afrin. It is also active in the Euphrates Shield area.

The groups in Idlib are holding talks about joining with the National Army.

Daesh (ISIS)

Daesh was born in Iraq in the early 2010s, taking advantage of the power vacuum created by the United States' withdrawal from the country, without leaving a strong Iraqi army behind. After the civil war broke out in Syria, they shifted to there and took control of most of the north.

The internationally designated terrorist group declared a "caliphate" in July 2014, whose borders included about one-third of both Syria and Iraq.

After the US set up an international coalition to fight against Daesh, the group started losing territory to the YPG and the Syrian regime, leading the two groups to control most of the country. Daesh has a small presence only in northern Hama now, with around 300 members.

The YPG

The People's Protection Units (YPG) is the fighting force of the Democratic Union Party (PYD), which was founded in 2003 against the Assad regime. The YPG was armed in 2011, shortly after the Syrian civil war erupted. Despite the fact that they opposed the regime since 2003, they had indirect co-operation with Assad during the civil war.

First, regime forces withdrew from the areas that the YPG claimed to be under their control.

Then, the regime protected them against any Turkish operation in Manbij by moving to the area and creating a buffer zone between the Turkish-backed FSA and the YPG.

But why would Turkey start an operation against the YPG? Because the group is the Syrian affiliate of the PKK, a designated terror group by Turkey, the US and the European Union. Turkey considers the groups to be a threat to its national security, since they have been fighting the Turkish state for more than 30 years, leading to the deaths of more than 40,000 people, including civilians.

Besides the indirect co-operation with the regime, the United States has been the biggest supporter of the YPG. The US trains, arms and uses the YPG as a key ally on the ground in the battle against Datamesh. 

In the beginning of February, the US hit the pro-regime forces in Deir Ezzor in a response to their attacks against the YPG, to show its full support for the group. 

The group was initially based in Kurdish-majority regions of northern Syria, but then expanded southwards towards non-Kurdish regions with the help of the US. And even after the fight against Daesh mostly ended, the US kept its support for the group and created a new army out of YPG militants in a move that angered Turkey.

On January 20, the Turkish army began Operation Olive Branch in Syria’s Afrin to eradicate the YPG and Daesh remnants from the region. The YPG deployed more militias to Afrin through Shia-militias and regime-controlled territory, which was another sign of their co-operation.

Iranian-backed Shia militias

Shia militants in Syria include the Hashd al Shaabi members from Iraq, Iran's the Islamic Revolutionary Guard Corps (IRGC), Hezbollah fighters from Lebanon, and Shia groups from Afghanistan and Pakistan who were trained in Iran by the IRGC. 

They were sent to Syria after the civil war broke out by Iran in order to protect Iran's long-term ally Assad and his regime. All the militias around Syria are commanded by Iranian General Qasem Solemani, who is the commander of the Quds Force, a part of the IRGC responsible for the cross-border operations.

The main objective for Iran, and for its proxies in Syria, is to keep Assad in power. This is why they have different enemies and are collaborating in different parts of the country. In one hand they are fighting the US-backed YPG for more territory in Idlib and western Aleppo, on the other hand they are co-operating in Afrin against the Turkish army.

They are also fighting against Turkish-backed opposition groups in Idlib along with the regime forces.

Hayat Tahrir al Sham (HTS)

Hayat Tahrir al Sham (HTS) was formerly known as Al Nusra Front, and was al Qaeda's Syrian branch. 

In July 2016, it was joined by other small groups in Idlib and rebranded itself as HTS, and said it broke off formal ties with al Qaeda. But the international community still considers the group an affiliate of al Qaeda.

In January 2017, it merged with four smaller opposition factions and has expanded its presence in Idlib, as well as north of Hama, and western Aleppo.

The group now controls much of Syria's Idlib province.