What is drawing soldiers like John Robert Gallagher into the fight against ISIS?

The story of a former Canadian soldier who died on a Syrian battlefield fighting ISIS militants may prompt many to ask why a person would choose to join a fight so far from home.

The Syrian Observatory for Human Rights has reported that John Robert Gallagher died Wednesday, during a suicide attack by an ISIS fighter.

• Mother of John Gallagher, killed fighting ISIS, remembers son as human rights activist

The slain soldier's mother, Valerie Carder, told CBC News that her son should be remembered as a person who was a passionate defender of human rights.

Gallagher had studied at York University, where a professor had urged him to take up a PhD, rather than the fight in Syria.

But he could not be dissuaded and in May he volunteered with Kurdish forces in northern Iraq, before he crossed into Syria in July. A few months later, he was dead.

Mathew Hughes, an American who fought alongside Gallagher in Iraq and Syria said Gallagher was motivated by strong political beliefs, calling him a scholar rather than a soldier.

He'd spent about four months with Gallagher overseas and plans to return soon. For him, the fight is about justice for the Kurds.

"John did a much better job of explaining it, but the Kurds are one of the largest ethnic minorities in the world without their own country," Hughes said in an interview with CBC News. "They've been stepped on by every major superpower in the region."

"Now out of the chaos Western societies have created in the Middle East they're finally taking a stand and trying to hold their own ground."

Carl Hospedales, a Windsor-based counter-terrorism expert, said many of the westerners fighting ISIS in Syria are people like Gallagher military veterans with a desire to do what they believe is right.

"Most of the men and women are former military personnel who have a very strong moral code,"he told CBC Radio's Windsor Morning on Friday.

Hospedales said these individuals know the risks, but they believe in the fight that is taking place.

"For former military personnel to go out there and support the indigenous people, it's not a big thing, but it has to be morally correct."

Hospedales said it is hard to say how many other Canadians may be engaged in fighting in Syria, just as Gallagher was.