Nasser and Aseel Muthana

Nasser Ahmed Muthana (born April 29, 1994) and Aseel Muthana (born November 22, 1996) are two brothers from Wales who travelled to Syria and joined the Islamic State of Iraq and the Levant as teenagers. Nasser joined first, travelling to Syria in November 2013. Aseel followed him in February 2014. The brothers were active on social media and Aseel has been interviewed several times by British media outlets. Both men have been sanctioned by the United Nations Security Council. Nasser is believed to have been killed in 2016. Aseel surfaced in Syrian prison in 2019 and said he wanted to return to the United Kingdom. As of 2021, Aseel is imprisoned in Syrian Kurdistan.

Background and recruitment to ISIL Nasser and Aseel were both born in Cardiff, Wales and grew up in the Butetown area of the city. Their father, Ahmed, is an electronics engineer born in Yemen, and they have two brothers. As children the boys attended St. Mary the Virgin Church in Wales Primary School and were high-achieving students.

Before leaving the UK, Nasser attended St. David's Catholic College, got all A grades on his A-levels and planned to study medicine. He had a temporary job with the Cardiff council. He dreamed of becoming a teacher.

Ahmed said he thought his sons had become radicalized by another person, whom he said had encouraged them to go to Syria and had given them the video game Call of Duty. The mosque where the brothers worshipped, Al Manar Centre, suggested they were radicalized online. Aseel and Nasser's brother said they "felt guilty about what was happening in Syria." Rahman stated he thought Aseel was going to Syria "to help people" and did not realize he was going to join ISIL.

ISIL Nasser took the nom de guerre "Abu Al-Yemeni Muthana" after he joined ISIL. He married a British-Bangladeshi woman. Ahmed stated Nasser had two sons; the BBC has reported that he has one son. Aseel took the nom de guerre "Abu Fariss" and married a British-Somali woman, 18-year-old Nasra Abdullahi Abukar, and they had two sons. The BBC reports that Aseel was married twice. In the video, Nasser said ISIL had fighters from as far away as Cambodia, Australia and the UK, and said, "We understand no borders... We will even go to Lebanon and Jordan with no problems". Nasser later called his mother and said ISIL had written the script for the video and forced him to appear in it. He denied having been radicalized at his mosque in Wales and said Nasser had taught him about jihad when he was young. He said, "I was always pro-jihad but didn’t approach the local imams or my parents because we knew it would brought us [ sic] trouble." He said he had pledged allegiance to Abu Bakr Al-Baghdadi and would remain in Syria unless Baghdadi told him to go elsewhere, and that he had no intention of returning home. The Times, using facial recognition software, subsequently determined that Nasser was not the man in the video. In September, Aseel was also added to the list. Ahmed called the sanctions "crazy", saying there were no assets to freeze.

Nasser had an active social media presence and regularly posted ISIL propaganda to his social media accounts, including photos of homemade bombs and weapons, and comments that the UK "should be afraid" of him if he were to return. When his brother arrived in Syria, Nasser tweeted that if a 17-year-old boy could do it, so could all Muslims.

In 2016, Brekke, Rahman and Ulhaq were convicted of preparation of terrorist acts and Ulhaq was also convicted of funding terrorism, for helping Aseel go to Syria. Ulhaq was released in April 2018, but recalled only three days later for breaching the terms of his parole.

Nasser and Aseel kept in touch with their parents after travelling to Syria, and reportedly told Ahmed that ISIL had treated them badly, including by forcing them to marry, and that they regretted leaving Wales.

The Independent mistakenly reported that Nasser was killed in an airstrike in 2015, but his parents continued to hear from him after that. In around 2017, the brothers stopped contacting their parents. She had had her British citizenship revoked in 2017 for joining ISIL. Her mother said she wanted to go to Somalia, where her father lived.

Aseel told ITV News that he and Nasser had joined ISIL "way before the caliphate was pronounced. Before all of these beheading videos, before all of the burnings happened, before any of that stuff. We came when [ISIL] propaganda and [ISIL] media was all about helping the poor, helping the Syrian people." In an interview with The Independent, Aseel said Nasser was responsible for convincing him to come to Syria. He said he began to have doubts about ISIL once they started executing western hostages. Mohammed Ismail, the third British fighter who had appeared alongside Nasser in the "There Is No Life Without Jihad" video, was executed by ISIL as a spy a few months later, after confessing that he had passed on information about Nasser's whereabouts to western intelligence agencies.

In 2022, Brekke was sentenced to nine months in jail for four breaches of his release; he had failed to notify the police about two cars he was using and two financial accounts he had opened, something his lawyer characterized as "a couple of silly decisions over a short period of time". In 2024, Ulhaq was sentenced to two years and nine months in prison after pleading guilty to five counts of breaching the terms of his release. He had been required to keep the police informed of all new email addresses, bank accounts and phone numbers and had failed to do so.