Tiger Sun described seeing a little girl who had been blown up by a landmine die because the Kurds had no medical training.
She also revealed how she had stepped on a charred finger while on patrol - but could not even find the body it had come from.
The former model, 46, fought jihadist fighters from Islamic State for four months with the Kurdish YPJ (People's Protection Units), until her legs buckled under the weight of her kit and malnutrition. This finally forced her to return home to Canada.
Tiger revealed that while women fight alongside male soldiers, sexual relationships do happen, although they are kept secret.
But she said despite being a ex-model she was treated as an equal during battle.
In an exclusive interview with MailOnline, Tiger said: 'I witnessed things I never could have imagined.
‘I stepped on a finger once - it was charred black and bent at a weird angle. The body it came from was nowhere in sight.
‘I watched a little girl die from her injuries from a landmine explosion because the Kurds have no medical training or equipment.’
The mother-of-one, who was born in Zambia, left Vancouver, Canada, for the battlefields of the Middle East after a Lebanese man she was in a relationship with left her for an arranged marriage.
She also saw an ISIS propaganda video featuring John McGuire, a white convert jihadist, from Ottawa, and it prompted her to go and fight.
On March 1 she left behind her grown up daughter from a previous relationship and flew to Iraq where she was smuggled through the country and into Syria.
With no real training other than how to fire a gun, she was thrust straight into battle.
'Did I see violence? Did I see ISIS kill innocent people? Yes, I was in the fight. I saw them trying to kill us. We see Daesh (ISIS), we kill Daesh, and that's about it. It's actually quite simple.
I had lunch by a pile of brains once. It was no big deal
'To be honest, the bodies don't haunt me. The friends I lost do make me sad though, and the unfairness of it all upsets me.
'When I saw friends killed I cried a little, but you just have to accept that this happens in war,' she explained. 'It's incredibly unfair but it's the reality in those circumstances.
'It still makes me cry when I think about it.
'Yazidis, Arabs, Kurds. Everyone has lost someone it seems. Many join the YPG or YPJ for revenge, or because they no longer have a family.
'They seem to hide their mourning though. I rarely ever saw anyone cry.'
Tiger witnessed death and destruction every day while fighting ISIS.
In June her group seized control of Tal Abyad – in the north of Syria, close to the border with Turkey – a key town used by ISIS to exports goods such as black market oil into eastern Syria.
The person in the trench next to you could be a guy or a girl and it makes no difference. They're soldiers first. Not once did I feel harassed, objectified or in danger when I was around the men
In battle Tiger fought with a woman who shot 28 jihadists dead – although she never killed anyone herself.
‘They were always just out of range,’ she said. ‘I brought my own pair of binoculars with me because they weren’t readily available, so I was doing a lot of the spotting, which led to kills.
‘I would go and look at the bodies afterwards, but it didn't and still doesn't bother me. I had lunch by a pile of brains once. It was no big deal.
‘However, I saw those who did kill someone go through a whole range of emotions, like elation, then guilt, and I realised if I did kill someone directly, I may obsess about it and ruin the rest of my life.’