A decade since South Sudan split from the northern rump state, old comrades left behind in Sudan still continue their fight against Khartoum -- despite strongman Omar al-Bashir's overthrow in 2019.
Holdout rebel commander Abdelaziz al-Hilu leads a faction of the Sudan People's Liberation Movement-North (SPLM-N) and first took up arms 36 years ago, battling what he said was the marginalisation of African minorities by an Islamist and Arab-dominated government.
While Hilu has signed a cessation of hostilities deal with Khartoum, long-running peace talks with the rebels -- who control enclaves in South Kordofan and Blue Nile states -- were suspended last month pending "consultations".
Hilu's SPLM-N was once part of the rebel force fighting a 22-year civil war against Khartoum in which hundreds of thousands of people died, that ended in a 2005 peace agreement.
For South Sudan, that deal paved the way for a referendum on independence and its eventual secession as the world's newest nation on July 9, 2011.
But as South Sudan celebrated, old guerrilla allies across the new border in Sudan -- also home to many Christians and traditional religions -- were left on their own in an overwhelmingly Muslim nation.
Any hope that "popular consultations" between rebels and the government in Khartoum might bear fruit had collapsed in heavy fighting with the army in June 2011, a month before Juba broke away.
"After the secession, he (Hilu) was like an orphan ... and was left to fight another day," said Sudanese analyst Magdi el-Gizouli of the Rift Valley Institute think-tank.
Guns for 'self-protection'
Grinding conflict in Sudan's southern regions dragged on for years.
In 2017, a power struggle split the SPLM-N in two.
One faction, led by veteran fighter Malik Agar, signed a historic peace deal in October 2020 alongside rebels from the western Darfur region, after their former arch-enemy Bashir was toppled as president in 2019.
Since then, Agar has become a member of the country's ruling sovereign council.
Hilu instead signed a separate ceasefire deal, insisting that his forces keep their guns for "self-protection" until Sudan's constitution was changed to separate religion and government.
Hilu, a Muslim, told Sky News last year the fact state and religion are not separate in Sudan was at "the root of the Sudanese crisis which led the country into multiple civil wars" since independence from Britain in 1956.
Born in 1954 in the rugged Nuba Mountains of South Kordofan, Hilu studied economics at university in Khartoum, and began his rebel fight in 1985.
He rose rapidly through the ranks to become a "respected guerrilla fighter" also labelled "the man of difficult tasks", according to SPLM-N members.
The old fighter is wary of joining his former enemies in the national army.
Last month, Hilu's chief negotiator at dragging peace talks told AFP one of the key unresolved issues was the integration of rebels into the army.
Hilu was not available for comment.
But Gizouli believes his calls for secularism to be a negotiating "tactic".
"He (Hilu) wants to keep his forces intact and doesn't want them to be absorbed into the Sudanese army," Gizouli said.
"If the issue of (keeping) Hilu's forces was resolved, he will be open to reaching an arrangement around secularism."
'Surviving on little'
There are some positive signs.
Last month, United Nations aid workers made a "significant breakthrough" when they were able to access "five isolated enclaves" -- home to some 800,000 people -- controlled by Hilu's SPLM-N "for the first time in 10 years", UN agencies said in a joint statement.
"Findings from this mission are bleak," said Abdullah Fadil, head of the children's agency UNICEF. "These children have been entirely 'left behind'."
The areas had been "largely been cut off from support" with people "in dire need" of food, health, education and clean water, the UN said.
"Communities in these areas have been struggling and surviving on little or nothing for a decade," said Eddie Rowe, World Food Programme chief in Sudan, after the delivery of 100 tonnes of food last month.
Still, the gradual opening of the enclaves offers a glimmer of hope, even if the peace talks are likely to take time.
"With improved food security and other opportunities, families will be able to reintegrate with the rest of Sudan and start to recover and rebuild," Rowe said.
However, Jonas Horner of the International Crisis Group warned that rebels and traditionally marginalised communities still see the civilian-led government in Khartoum as offering little solution to their woes.
"Until more representative governance is in place, significant change in these enclaves -- or even across Sudan's peripheries more broadly -- is unlikely," Horner said.