When protests first flared in 2011 against Syrian President Bashar al-Assad's regime, Ahmad Mansour took to the streets of Aleppo with his high school-age peers. But as the uprising morphed into armed clashes, he joined the ranks of the armed opposition. Ten years later, he is still fighting. Now the head of his own battalion in Idlib, the 26-year-old has lost countless comrades, but his stance against Assad is unwavering.