A 24-year-old American video gamer who quit his job and flew to Syria to fight ISIS claims he survived thanks to skills he learned playing Call of Duty.

John Duttenhofer, of Colorado, traveled to Syria last April to fight alongside the Kurdish People's Protection Units, or YPG, in Raqqa as they worked to liberate the city from ISIS.

The former customer service worker said that playing first-person shooter games for up to 13 hours a day gave him an understanding of weapons and taught him basic combat skills before he went to Syria.

He spent six months fighting ISIS in the caliphate's de-facto capital, which was finally liberated in October.

Duttenhofer returned to the United States four months after suffering the loss of his close friend Jac Holmes, 24, a British IT worker who was killed in an explosion last October.

John Duttenhofer, of Colorado, traveled to Syria last April to fight alongside the Kurdish People's Protection Units, or YPG, in Raqqa as they worked to liberate the city from ISIS

Duttenhofer spent six months working with the YPG until Raqqa was liberated from ISIS last October. He credits first-person shooting games for helping him survive in Syria

Duttenhofer, pictured center with his friend Jac Holmes (right) and another comrade, worked alongside a sniper unit of Kurdish soldiers as they occupied empty buildings and shot at ISIS fighters in a bid to advance.

Raqqa, which sits on the banks of the Euphrates River with a population of about of 200,000, was the first city to fall into the hands of Islamic State militants

Speaking for the first time since he returned to Colorado on February 12, he told how he whiled away his days in Syria playing Dungeons and Dragons, reading and chatting with friends.

By night, he went deep into the city with an AK47 alongside a sniper unit of Kurdish soldiers as they occupied empty buildings and shot at ISIS fighters in a bid to advance.

While the State Department strongly advises against Americans traveling to Syria, there are no legal consequences to volunteering to fight ISIS with Kurdish and Syrian militias.

Duttenhofer said that war-reenactment games like Call of Duty taught him practical skills which he used to survive and meant he was already familiar with weapons.

He also said he was 'disappointed' he didn't end up killing any ISIS members, but he saw his 'battle buddies' - including Holmes - fire fatal shots.

'I had no guilt about it,' he said of rebel lives being lost. 'They are a group worse than the Nazis. They want to live the dark ages out again and I didn't want to live in a world with them.'

Despite the threat of death, Duttenhofter revealed that the thing he struggled most with was the lack of home comforts like air conditioning and chocolate milk.

Duttenhofer is now back home living with his bookkeeper mom Sherie and delivery driver dad, David, who he said were worried when he told them of his plans to go to Syria.

'My mom tried to persuade me to stay but she knew that fighting me would just make me go more rushed and unprepared,' Duttenhofer said of his plans to go to Raqqa.

Duttenhofer, pictured right in a sniping nest, said that war-reenactment games helped him with survival skills

Duttenhoffer, pictured left with comrades also from outside Syria, said he was 'disappointed' he didn't end up killing any ISIS members while in Syria

Duttenhofer's friend Jac Holmes (pictured) was killed in an explosion while clearing landmines in Raqqa in October 2017, a week after the terrorists' de facto capital was liberated

Duttenhofer said that games like Call of Duty (a still pictured above) taught him practical skills which he used to survive and meant he was already familiar with weapons

Two years before Duttenhofer arrived in Syria in 2016, Raqqa had become ISIS's de-facto capital.

The city was regularly hit by airstrikes from the Syrian government, Russia and the United States as they tried to rid the city of rebels.

Following a lengthy battle in October 2017, the Syrian Defense Forces (SDF) - its main backbone being the YPG - declared the city liberated from ISIS.

Over seven years, Syria's civil war has killed hundreds of thousands of people, forced millions from their homes and disturbed the regional balance of power.

Most recently, eyes have turned to Damascus, where Syrian airstrikes killed nearly 130 people in two days this week.

The violence in the capital and nearby areas came as scores of pro-government gunmen began entering the northern Kurdish enclave of Afrin – where Turkish forces are fighting Syrian Kurdish troops (the YPG) in a separate offensive.

Suburbs targeted by the Syrian government - scattered across an area known as eastern Ghouta - have been subjected to a weeks-long bombardment that has killed and wounded hundreds of people.

While it's now liberated, Raqqa was the first city to fall into the hands of Islamic State militants and became its de facto capital. Under the fanatics' reign atrocity followed atrocity - including the beheading of Western hostages by Jihadi John, and the mass murders of the Islamic fundamentalists' rivals and the civilians under their rule.

Duttenhofer said of traveling to the country: 'On one hand, I selfishly wanted to fight ISIS. On the other I wanted to be a part of something that was historical and groundbreaking. I wasn't scared of dying or anything like that.

Duttenhofer, pictured left in his younger years with his older sister and right in 2010, said he felt 'socially awkward' growing up and 'didn't have a lot of friends'. He ended up exploring the outdoors and playing video and computer games to pass the time

While in Syria, Duttenhofer said that he became 'battle buddies' with Holmes, a British volunteer from Bournemouth, Dorset, who was killed in an explosion last October. The tragedy prompted Duttenhofer to leave Syria, and he flew out of Iraq on November 16

How Raqqa first fell to the Islamic State and became the caliphate's de-facto capital before liberation last year Raqqa, which sits on the banks of the Euphrates River with a population of about of 200,000, was the first city to fall into the hands of Islamic State militants. Free Syrian Army rebels and al-Qaida fighters seized the city in 2013, bringing with them Sunni jihadis from the Islamic State of Syria and Iraq, known then mostly as ISIS. The jihadis, in turn, expelled al-Qaida and the moderate opposition fighters from the city in January 2014 and set about transforming Raqqa into the de-facto political capital of their soon-to-be declared 'caliphate.' Self-proclaimed IS caliph and the head of the militant group, Abu Bakr al-Baghdadi (pictured), hoped to turn Raqqa into IS's de-facto capital IS razed Raqqa's main Shiite mosque and converted churches into Islamic centers. Christians and other minorities were persecuted; most fled the city and the rest were compelled to pay a special tax. Self-proclaimed IS caliph and the head of the militant group, Abu Bakr al-Baghdadi, called on doctors and engineers to travel to Raqqa to help build his 'caliphate' and realize the dream of global jihad. Foreign fighters flocked to the city from around the world, with the Syrian government, Russians and US troops dropping air strikes. Schools were closed, and children were sent to mosques for indoctrination into jihad and camps for military training. Foreign journalists and aid workers were held in the city's prisons and beheaded in videos that brought the IS militants the global attention they craved. Thousands of civilians and SDF fighters were killed as a battle raged on to liberate Raqqa from ISIS. In October 2017, the city was declared liberated Planning for some of the major attacks in Europe in recent years, including the 2015 Paris attacks, which killed 130 people, and the 2016 suicide attacks on the Brussels airport and subway, which killed 32, was traced back to Raqqa. In June 2016, a Kurdish-led group called the Syrian Democratic Forces launched operations to capture the city. Backed by US airstrikes and artillery fire, it took the SDF four months of street fighting to recapture Raqqa. As the battle dragged on, the US-led coalition intensified its bombardment. The coalition dropped more shells and bombs on Raqqa in August 2017 than it did on all of Afghanistan in the same month, according to Airwars, a group that monitors the human cost of the US and Russian air campaigns in Syria and Iraq. Thousands of civilians and SDF fighters were killed as a battle raged on to liberate Raqqa from ISIS. In October 2017, the city was declared liberated. Source: Associated Press Advertisement

'Video games prepared me in a way for knowing strategies and how not to get killed, like how to use cover and not to stand in the open.

'They weren't something I picked up because I was going out there to fight, but as a kid I played every day after school. I could sit down and put 13 hours in like it was nothing.

'The Americans would give Claymore mines to the YPG and a lot of Syrians didn't know how to use that stuff, even though they have been living in a war for six years.

'I don't think you can really draw a comparison between the mental state of mind of playing a game and going out and potentially losing your life.

'In a game you will get shot and you quickly learn if you are killed, but in real life you just die.'

Growing up, Duttenhofer played computer and video games, went to shooting ranges and enjoyed exploring outdoors, but felt 'socially awkward' and 'didn't have a lot of friends'.

He finished high school with 'poor grades' before entering started working in customer service for a software company.

The 24-year-old decided to go to Syria at the end of 2015 after reading about atrocities committed by fighters from the so-called Islamic State and the fight for Raqqa.

He sold his car, saved $7,000, got fit by cycling to work and bought binoculars, weapon slings, AK-47 magazines and ChapStick on Amazon before setting off on April 23, 2017.

The journey, which cost around $1,000, saw him travel to Germany to avoid detection before flying from there to Sulaymaniyah in Iraqi Kurdistan.

From there he dialed a number provided by the YPG - whom he had contacted online - and was instructed to check into a hotel, where he was picked up by a co-ordinator.

The 24-year-old decided to go to Syria at the end of 2015 after reading about the Civil War. The journey to the country cost him approximately $1,000

While on post in Raqqa, he was in danger from both ISIS and airstrikes. Pictured above, a nearby artillery strike

IS razed Raqqa's main Shiite mosque and converted churches into Islamic centers. Much of the city was destroyed during IS's occupation. PIctured above, Kurdish fighters walking through Syria last week

He and 12 other volunteers from the US, Spain, Germany, Britain and Ireland, then crossed mountainous terrain and went over the border into north-east Syria in May.

Duttenhofer - who says he has constitutionalist, libertarian views - said he then spent a few weeks at an academy learning basic Kurdish and undergoing weapons training.

The group was divided into three, with Duttenhofer and three other westerners joining a group of Kurdish fighters east of Raqqa for the first three weeks.

He later joined a sniper group based in the heart of the capital, close to the Old City Wall, and was in a unit that was attached to other fighters and provided backup.

It was there that where he went into battle armed with an AK47 and his history of playing video games came in useful.

Duttenhofer said: 'Typically we would be looking for ISIS, for cars, for heavy weapons or rocket launchers. A group goes forward, occupies a building and tries not to die. ISIS are totally blasé, walking around.

'There was one time when we started picking holes and looking at a neighboring building that was being attacked and spotted an ISIS fighter.

'I didn't know he was ISIS at the time so I called him over and he leans over and does a sideways gang sniper spray. He had a black mask tied around his face.

'Jac quickly put three rounds through his M-16 before the guy was done with shooting.

'We left the position so as to not take return fire. Some moments later I took a look at the position through binoculars and the man was gone. We later found that there was a splat on the wall.'

Before heading to Syria, Duttenhofer (center) sold his car, saved $7,000, got fit by cycling to work and bought binoculars, weapon slings, AK-47 magazines and ChapStick on Amazon before setting off on April 23, 2017

Duttenhofter saw a failed explosive car in front of an ISIS billboard while walking the streets of Raqqa

Following a lengthy battle in October 2017, the Syrian Defense Forces (SDF) - its main backbone being the YPG - declared Raqqa liberated from ISIS

While in Syria, Duttenhofer said that he became 'battle buddies' with Holmes, a British volunteer from Bournemouth, Dorset, who was killed in an explosion last October.

Holmes, also 24, had no military training and was killed a week after Raqqa was liberating.

As a former IT worker, Mr Holmes had no previous military experience, but he became one of the longest-serving foreign volunteers in the conflict. He was also known by his Kurdish nom de guerre Sores Amanos - 'sores' meaning 'revolution'.

Holmes' death prompted Duttenhofer to leave Syria, and he flew out of Iraq on November 16.

He then spent two months in Europe, including attending a memorial ceremony for Holmes, before returning to the United States earlier this month and arriving back in Colorado on February 12.

He is now back at home with his parents and trying to adapt to 'normal' life.

He said: 'I feel like I'm still the same person. I'm not the tough guy now or anything. I'm not a changed man, but I would like to think I am wiser for it.

'Before I went I wasn't satisfied with getting up and going to work because the lifestyle in general felt like I wasn't doing anything.

'It is like two worlds and I wanted to get the most out of one by being in it and actually fighting. Now I'm back in this world and I want to live to the fullest and enjoy everything.

'I'm going to smoke as much pot as I can, eat ice cream, drink chocolate milk and hang out with my friends.'