RSF forces have captured el-Fasher, the Sudanese army's last stronghold in Darfur, marking a major shift in Sudan's civil war. Army chief Abdel Fattah al-Burhan says troops withdrew to avoid further destruction. The UN warns of a "catastrophic" humanitarian crisis, with reports of executions, ethnic cleansing, and civilians held for ransom. Thousands flee to overcrowded camps as regional powers back opposing sides.