Warmatrix

Daesh is the Arabic acronym for Islamic State of Iraq and the Levant. It is a terrorist group that has gained enough power to lay claim to the title of a theocratic islamic state, though not a single other state recognized it as such. Since its origin, it has been fighting to establish itself.
When the USA, Britain and a handful of other countries invaded Iraq in 2003 CE, they quickly toppled the regime of dictator Saddam Hussein. Lack of vision from both the coalition and the new shiite dominated Iraqi goverment led to instability that enabled small groups to take some power in Iraq. One of these was the Jama'at al-Taw'id wa-al-Jihad, a political salafist fundamentalist group established in Jordan in 1999 CE, which had ties with al-Qaeda and other terrorist organizations. After its leader was killed in 2006 CE, it merged with several other groups and changed the name to ad-Dawlah al-'Iraq al-Islamiyah, the Islamic State of Iraq.
This started out as a small group of around 1,000 fighters, competing for power with other sunni groups. At first it was limited to conducting terrorist attacks, then gained control over parts of western and central Iraq. American troops started to hit it hard and almost destroyed the group in a military sense, yet failed to grasp the strategic situation. Because the shiite majority that dominated the new Iraq was increasingly marginalizing the former Ba'ath party and its sunnite power base, the latter joined with the fundamentalists, providing military experience and support in the sunni areas of Iraq. Through swift victories and defection of Iraqi forces they also gained heavy weapons. More and more the group became a sunni Iraqi rebel movement.
In 2011 CE the outbreak of the Syrian Civil War enabled the group to gain a power base in Syria and become a combined Iraqi-Syrian organization. It cut its ties with al-Qaeda and proclaimed the Islamic State of Iraq and the Levant ("Da'ish" or "Daesh" in Arabic). Its numbers grew, to 100,000 or possible twice as many. Soon it drove the Iraqi army out of western Iraq, captured Mosul and large parts of Syria. This prompted a reaction from Iraq, Syria and various allies, who started to eliminate Daesh.
Since its beginning, the army of Daesh has been a mix between terrorists and a regular army. For defense, fighters mingle with civilians to protect themselves from air attacks. For attack, they infiltrate villages and towns to spot strongpoints and leaders long before the real military offensive, so that the soldiers know exactly where to strike. In these attacks, Daesh used heavy weapons that were captured from the armies of Syria and Iraq. When faced by strong counterattack, units dissolve and if pressed hard, fall back on terrorist tactics. Many attacks are conducted with explosives, used in car bombs and by suicide attackers. Many Daesh soldiers fight with fanatical religious zeal, though fear from those in command is an equally powerful motivator.
Strategically, Daesh aims to bring back the time of islamic conquests and drive a wedge between (sunni) muslims and the rest of the world. The latter are to either join their cause, submit or be downright exterminated. The end goal is a world-spanning islamic caliphate, which was actually proclaimed in 2014 CE when Daesh renamed itself to Islamic State. Some fundamentalist groups in other countries in Africa and Asia have pledged allegiance to Daesh, though they do not form a full political or military union.
In both war and government, Daesh and its predecessors have displayed an unprecedented level of barbarism. Laws of war were completely ignored; soldiers and civilians were targeted without distinction; rape, torture and beheadings of captured enemies were common; children were used as soldiers. In captured regions, some religious and ethnic groups were persecuted in genocidal campaigns.
This disregard for humanity, combined with the threat of expansion, has mobilized many states against Daesh. Neighboring countries fought back; in 2014 CE the USA and most other western countries joined in. Three years later Daesh was driven out of Iraq. In 2019 CE the last remnant of Islamic State was destroyed in the battle of Baghuz Fawqani. Though the state is gone, many Daesh fighters have gone underground, reverting back to terrorism.