Sudan, a vast country of 45 million people, has a long history of inequality and strife involving ethnic minority groups in remote regions.
Since its days under British rule, "Sudanese political society has been centralized in the Nile Valley," said Marc Lavergne, a specialist on the Horn of Africa and the Middle East.
Even after independence in 1956, "there has been this dichotomy between the Nile Valley, Khartoum, the parts that the British could make use of," and the rest of the country, he told AFP.
The more remote areas experienced decades of struggle "that no Khartoum government cared to address," said Lavergne of France's University of Tours, who has worked for U.N. and non-government missions in Sudan.
"But today these peripheral regions hold the richest potential," he said, referring particularly to large gold deposits in Darfur and elsewhere, from which Rapid Support Forces [RSF] general Mohamed Hamdan Dagalo has built a military and economic empire.
A Rift Valley Institute report judged that, as a result, "the RSF is no longer a rag-tag militia but rather a well-trained and effective fighting force that can rival" the Sudanese Armed Forces.
"The current conflict represents a battle between the established military-political elite from the center [Sudan Army General Abdel Fattah al-Burhan] and an emerging militarized elite from Darfur to control the state, and is a new phase in the struggle between center and periphery."
- Intruder from Darfur -
Dagalo has been depicted by his rivals as "an intruder from Darfur in more cosmopolitan Khartoum," said Kholood Khair, founder of the think tank Confluence Advisory.
"Before the war, the RSF were getting some traction in trying to create a narrative that they were fighting for democracy, and that they were doing so on behalf of all the marginalized people of Sudan," she told AFP.
As he built his force, Dagalo became "one of the best employers in the country", recruiting fighters from areas "that had historically been marginalized by Khartoum," according to Khair.
But she added that, "once the war broke out, that narrative became more difficult to keep up" as "his troops are far less disciplined" than those of the regular army.
"They do not always follow orders and have been creating a lot of havoc for the people of Khartoum," she said, as reports of assaults against civilians, looting and home invasions have risen sharply.
The threat of deepening ethnic strife looms over Sudan, a diverse country at the intersection of historical migration and trade routes with a history of slavery.
Its rulers have historically exploited economic inequalities to divide and conquer, between the core and the periphery, between north and south, and based on skin color.
"To this day, Sudanese have a lexicon of skin color" that discriminates against those with darker pigmentation, Sudan specialist Alex de Waal wrote recently in the London Review of Books.
"Both sides will, as they lose troops, need to recruit more," said Khair. "And the easiest way to do that in Sudan has historically been through ethnic allegiances."
Sudan War Shows Nation's Class Divisions
CAIRO - Sudan's brutal war has pitted the traditional urban elite that has long monopolized wealth and power in the capital Khartoum against forces from the marginalized rural periphery, analysts say.
