Levi Jonathan Shirley was killed on Thursday in the battle for Manbij, a city in northern Syria, 30 kilometers west of the Euphrates River.Kurdish and Arab forces from the Syrian Democratic Forces have been fighting to take Manbij from Islamic State for the last month in a major offensive.Shirley is the second American to be killed in Syria fighting ISIS as a member of the Kurdish People’s Protection Units (YPG).Shirley joined the YPG in February 2015, according to reports, and after returning to the US he went back in January 2016 to fight ISIS. He participated in the battle for Kobani, which became a symbol of resistance to ISIS. His mother, Susan Shirley, told reporters that he wanted to fight ISIS which he saw as evil because it was persecuting the defenseless.“He had a very big heart...He was so brave to go back the second time, knowing what he was in for. He just really cared about the underdog,” she said.He was 24-years-old. The Colorado-born man was known as Agir Servan to his fellow fighters. Most foreign fighters take on new names, and his meant “fire.” In a video released on You- Tube by the YPG he is memorialized and shown explaining his choice. “I came here to fight Daesh [ISIS], they are my definition of pure evil. I don’t think good people in a society can put people inside of a cage and set them on fire, I came here to stop that.”On a Facebook page under his Agir name his friends posted a photo of his backpack that included a drawing of a batman symbol and a Punisher logo from the eponymous comic book series. In a post from December 2015 he condemned rising anti-Muslim views associated with Donald Trump, “you can’t just arbitrarily kick out millions of law-abiding citizens because you don’t like their religion – that’s not an American value.”According to a comrade who goes by the name Jonathan Botan and is also American and Jewish and has been serving with the YPG, Shirley was Jewish but it was not something they discussed much, because they were in separate units. “I met him a few times, he was in a different unit.Didn’t know him too well but knew he was a great guy and a good soldier.”Botan thinks that “more Jews should get involved. As far as I know there were only four or five in total that joined the YPG.”Dozens of foreign volunteers have traveled to Syria to fight alongside Kurds in the battles against ISIS since 2014. The exact number of volunteers and where they are from is not known. In June the YPG erected a monument in Qamishlo to foreign volunteers who had been killed including Reece Harding from Australia and Chris Scurfield from the UK. At the time there were 10 images on it, with the death of Shirley and others in the battles for Manbij, more will be added to the list.