Intisar is 12 years old. She has never been to school. She used to leave peacefully on a farm with her mother and 14 siblings in rural Kass, southern Darfur, but then nomad militias arrived and started grazing their camels on her family’s land. Fighting in Darfur between Arab militias and rebel groups, which escalated in March this year, has driven an estimated 670,000 people from their homes, 70,000 of whom have fled across the border into neighbouring Chad.