For the past two decades, Ethiopian Prime Minister Meles Zenawi's iron-fisted rule was something Western nations depended upon in the volatile Horn of Africa region.
His death late on Monday has left a major power gap and raised questions about Ethiopia's role in the region -- including relations with arch-foe Eritrea and war-torn Somalia -- with analysts warning stability in the Horn will depend on a peaceful transition.
"Developments in coming weeks in Ethiopia have the potential to affect the Horn of Africa's political, economic and security landscape for years to come," said Jason Mosley, from Britain's Chatham House think-tank.
"For a country that has only had three changes of power since the Second World War, there is little useful precedent to shed light on how the process will play out."
The ex-rebel held a steely grip on power, jailing opposition and sidelining many within the ruling coalition, the Ethiopian People's Revolutionary Democratic Front (EPRDF).
Power for now passes to interim leader Hailemariam Desalegn, 47, a protege of Meles as deputy prime minister, but who is not believed to hold the full reins of control, with the EPRDF expected to elect a new party head in coming weeks.
"He is placeholder for now," exiled opposition leader and former mayor of Addis Ababa Berhanu Nega told the BBC.
But Mosley, of Chatham House, said the lack of unrest since June -- while the ailing Meles was absent -- suggests the leadership is capable of controlling a country with a history of military coups.
"Meles' disappearance from the scene for more than two months wasn't enough to shake its confidence... so if things can continue to go fairly smoothly in the next two weeks, then maybe they can get through this," Mosley told AFP.
The main threat to Ethiopia is "instability within the (EPRDF) coalition" said Roland Marchal, from the French National Centre for Scientific Research (CNRS).
There are also threats from armed groups in the rebellion-prone country, but while insurgents "may decide to launch an offensive", Marchal said he sees the strong army as capable of crushing the relatively small and isolated movements.
Others are hopeful that with the end of Meles's rule -- one condemned by rights groups for repression, but praised for its economic advances -- current stability can be retained.
"It is not unreasonable to conclude that a solid foundation has been laid upon which Meles Zenawi's successors can build, as they take the country's development and political evolution to its next stages," said J. Peter Pham of the Atlantic Council think-tank.
If that stability can be maintained internally, then regional relations may continue without major visible change, with Ethiopian troops expected to remain inside Somalia, where they are supporting the battle against the Al-Qaeda-linked Shebab insurgents.
"There won't be any change in our domestic policy or foreign policy," Ethiopia's foreign affairs spokesman Dina Mufti told AFP, insisting it was "business as usual".
While the Shebab said they were celebrating the "uplifting news" of Meles's death, little shift is expected on the ground.
"While it is true that Ethiopia has no desire for a lengthy stay in Somalia, it recognises it cannot leave the job half done," said Rashid Abdi, a longtime analyst on the Horn of Africa, estimating there are some 10,000 Ethiopian troops in Somalia.
Meles was also a key figure in crisis talks between rivals Sudan and South Sudan after they came close to all-out war following their separation last year, in a bitter dispute over oil, security and border demarcation.
"It's probably helpful that Meles was trying to push those talks... but I don't think (his death) is totally detrimental," Mosley said, noting negotiations were led by the African Union, not Ethiopia.
Meles's death could also potentially see changes in the relationship with arch-foe Eritrea, which split from Ethiopia in 1993 before the two spiralled into a bitter 1998-2000 border war in which tens of thousands died.
Asmara has so far made no comment on his death.
Some fear that a reshuffle of power could encourage rivals across the Horn to resume the practice of backing proxy forces to target each other's interests, including in Somalia, where Eritrea was accused of backing Islamist forces as a way to needle Addis Ababa.
"Eritrea will look to strengthen their position following his death, and Somalia will be once again caught up between the two countries as they seek to reposition themselves," said Joakim Gundel, a Nairobi-based academic.
But others suggest that for now there may be little change.
"Barring some dramatic gesture out of Asmara, I do not see any immediate movement," said J. Peter Pham of the Atlantic Council.
"While the new leaders do not have the baggage with (Eritrean President Issaias Afeworki) that Meles brought to the issue, they cannot afford to be seen by their domestic constituents as having 'gone soft'."