Since Islamic State (IS) militants swept through Iraq and Syria in 2014, calling into question what have become increasingly meaningless borders, one group has circumstantially found itself on the frontlines of the ongoing war: the Kurds.

But the Kurdish involvement in the battles can be difficult to understand because the poorly-understood Kurds have their own historic troubles with neighbouring countries in the region, as well as multiple internal rifts and factions.

Here, we break down the current Kurdish crisis into six simple questions:

Who are the Kurds?

The Kurds are the largest 'ethnic minority' in the world without a country of their own, with a population estimated to be somewhere between 25 to 40 million people.

Although the majority are Muslim and live in the heart of the Middle East, they do not identify as Arabs.

They speak Kurdish, have different cultural attributes, and a history more in line with that of the Persians.

That's simple. Then why do they seem so complicated?

Following World War I when the Ottoman Empire fell, the French and British drew up a new map with new states in 1916 known as the Sykes-Picot agreement.

Map of the Middle East showing Kurdish distribution. ( Reuters )

Although there was push for an official country of Kurdistan to be created, the Kurds did not receive fair representation and were subsequently divided into Turkey, Syria, Iraq and Iran, which has been at the core of the Kurdish dilemma for the last century.

Therefore they are the largest ethnic group in the world to not have a home state, and have since become the largest ethnic minority in four different countries.

The reason why the Kurds didn't get their own country is widely debated, but the short answer is usually a mixture of bad luck, tense relations with the Turks, and oil.

Hence the Kurds may be a single ethnic group, but the divisions over time have created numerous variations among the Kurdish peoples, country to country.

Most have adopted another national language as well as their own, and resist the Sykes-Picot agreement in direct proportion to the Kurdish policies of the country and circumstances in which they live.

Is that why they fall under so many different names?

Yes, the Kurdish separation has led to the creation of dozens of Kurdish splinter groups over the last century, ranging from highly militant to solely political.

Peshmerga Kurdish security forces take part in an intensive security deployment after clashes with Islamic State. ( Reuters )

Here is a list of the main groups at the forefront of the current crisis in 2015:

PKK: The Kurdistan Workers Party, formed in Turkey in 1978, took up arms in 1984 with the aim of creating an autonomous Kurdistan by force.

The move has led to decades of violent clashes that continue to this day, as well as the group being designated a terrorist organisation in 2002 by the US, Turkey and others, like Australia.

The PKK is now based in both Turkey and Iraqi Kurdistan, and despite being designated terrorists, they are also militantly opposed to the terrorism and extremism of Islamic State.

YPG: The People's Protection Unit, formed in Syria in 2004, is the armed forces of Syrian Kurdistan in the country's east which was ignited by the breakout of the Syrian revolution in 2011 as relations with Bashar al-Assad's regime broke down.

The YPG was then forced onto the front-lines in 2014 as IS made its way into Syria, and has been one of the Islamic State group's major opponents since.

Map The location of the different groups within unofficial Kurdistan borders

HDP: The People's Democratic Party formed in Turkey in 2012 with the aim of playing politics, becoming the first pro-Kurdish party in Turkish history to gain parliamentary seats in June 2015, breaking the party of president Tayyip Erdogan's 12-year majority rule.

The HDP is not militant, and their success has been attributed to their inclusive campaigning which endorses fringe groups like democratic socialists and the LGBT community.

Many analysts believe the HDP's parliamentary gains to be a primary cause of the reignited Turkish battles against the Kurds.

Peshmerga: Formed in northern Iraq in the 1920s, they are the armed unit of Iraqi Kurdistan in northern Iraq near Mosul.

After decades of heavy fighting, Iraqi Kurdistan was established in 1970, but only gained autonomy in 1991 under the Kurdistan Regional Government (KRG).

The Peshmerga, which not only helped the US capture Saddam Hussein during the Iraq War, has also been at the frontlines of the battle against IS as it swept aside the Iraqi army in 2014 and took over Mosul.

There are many other Kurdish groups, and alliances between the different groups themselves evolve over time, and hence are often unclear to those on the outside.

But underlying it all, they are united by ethnicity and an inherent longing for their own homeland.

Why are they so prominent in the fight against Islamic State?

Islamic State's large scale offensive through northern Iraq in 2014 consequentially brought neighbouring Kurdish militant groups to unite in a coordinated battle, and they have by far been the most successful at fighting the militant group on the ground.

YPG fighters take up positions inside a damaged building to monitor Islamic State militants. ( Reuters: Rodi Said )

One of the reasons why the Kurds are so effective in fighting IS is that, historically speaking, they are fighting on the same battleground, as IS also does not recognise the Sykes-Picot agreement and borders.

The Kurds are homogeneously well-organised throughout the border areas between Turkey, Syria, Iraq and Iran, which are not only mountainous, remote and difficult to navigate, but highly strategic.

Coincidentally, it is at the heart of the IS caliphate.

For this reason they have been far more effective than the Iraqi and Syrian armies, despite lacking the resources of the aforementioned armies — a matter of consternation for the past year.

Also, because of a long-subjugated hope for a recognised and unified Kurdistan, the fight for the Kurds is also inherently personal and historic as the battles against IS become opportunities to establish legitimacy on the international stage as a unified and very real group of people.

Every victory over IS therefore marks not only territorial points, but legitimacy.

If the Kurds are fighting IS, why is Turkey bombing them?

The Turkish and Kurdish standoff goes back decades and in the interim period the two have battled relentlessly over autonomy in Turkey's south-east.

Turkey has been bombing Kurdish militants. ( Reuters: Murad Sezer )

But the main reason why the fight with Turkey has kicked-off again is two-fold:

Firstly, in June this year, the first pro-Kurdish political party, the HDP, made history by winning seats in parliament, breaking president Tayyip Erdogan's majority control over the government and disrupting his ambitions of setting up a presidential system.

Secondly, in recent months, the Kurds' fight against IS has started to spill over Turkey's border.

Timeline of Kurdish sovereignty 1890s: Kurdish nationalism rises as the Ottoman empire begins to fall

Kurdish nationalism rises as the Ottoman empire begins to fall 1916: Following WWI, the Sykes-Picot agreement fails to incorporate the Kurds

Following WWI, the Sykes-Picot agreement fails to incorporate the Kurds 1920: Treaty of Sevres promises Kurdistan will be created

Treaty of Sevres promises Kurdistan will be created 1923: Turkey's president Kemal Attaturk rejects the treaty

Turkey's president Kemal Attaturk rejects the treaty 1924: Treaty of Lausanne, which doesn't include Kurdistan, replaces Sevres and is signed

Treaty of Lausanne, which doesn't include Kurdistan, replaces Sevres and is signed From 1925: Kurds in Turkey, Syria, Iraq and Iran fight for sovereignty

Kurds in Turkey, Syria, Iraq and Iran fight for sovereignty 1991: Iraqi Kurdistan becomes autonomous

Iraqi Kurdistan becomes autonomous 2003: Peshmerga help US capture Saddam Hussein in Iraq War

Peshmerga help US capture Saddam Hussein in Iraq War 2011: Arab Spring reignites Kurdish identity issues

Arab Spring reignites Kurdish identity issues 2014: Islamic State's offensive reignites Kurdish sovereignty issues

The Turkish government has maintained that the recent attacks against the Kurds are purely in retaliation for recent violence committed by the PKK against Turkey, but the conflicting narratives quickly devolve into "chicken or egg" arguments.

While the battle against IS presents a huge opportunity for the Kurds to project legitimacy on the international stage, this legitimacy presents a huge threat to countries like Turkey who historically do not want to lose territory to an autonomous Kurdistan.

However, as there are now many different Kurdish groups, striving for unity also invokes a double edged sword as governments, like Turkey, are able to group all Kurds together to score political points.

For example by equating the political HDP to the militant, "terrorist" PKK, and therefore by association through terrorism to the Islamic State group, political narratives rapidly spiral into generalised anti-Kurdish sentiment.

This lead to Turkish citizens recently raiding the HDP headquarters, even though the current crisis was instigated by the IS bombing of a pro-HDP Kurdish town.

This brand of convoluted political and territorial warfare has been going on in the region with the Kurds for decades — including in neighbouring Iraq, Syria and Iran — but the global fight against IS and the collapse of the borders on the ground has dragged the broader politics of the region out into the public eye.

OK, so why not just let the Kurds have Kurdistan?

This question is still being debated by analysts, and although it is far too early to draw any conclusions the stakes are higher than they have ever been for a redrawn Middle East.

As the different factions of Kurds unify and play pivotal roles in the international battles fought in the Middle East — such as with the Peshmerga helping capture Saddam Hussein, and now the Kurds' successful battles against IS — Western opinion of the Kurds and the future of a potential Kurdistan is shifting.

Nonetheless, for countries like Turkey, Syria, Iran, Iraq it is seen overwhelmingly as a losing deal. Significant territory, resources and strategic locations would have to be officially handed over.

But despite such hesitations, current battles along with the continued economic and political instability in Turkey, Syria, Iraq and Iran over time, will be central in determining the future shape of the region.