SANA'A // Yemen's president, Ali Abdullah Saleh, this week received the biggest blow yet to his hopes of staying in power when Yemen's top-ranking military commander demanded his resignation and promised to protect anti-regime protesters from assaults by security forces.
Few here deny that Major General Ali Mohsen al Ahmar has been a part of all political equations in Yemen for the past three decades. Thus, when the general refused earlier this week to give Mr Saleh the pledge of loyalty the president was seeking and changed sides, the mostly young protest movement received a potential saviour. To the public, he is an opaque figure, having succeeded for more than 15 years to stay out of the media spotlight.
Saber Ali, an expert in Saudi Yemeni affairs, said: "He is the opposite of President Saleh and his family, and it seems that al Ahmar has been busy organising his cards to take lead at a time like this." said
However, while it is difficult, if not impossible, to ascertain how a post-Saleh era under the heavy influence of Gen al Ahmar would evolve, his record contains some hints. For one thing, highly regarded political observers here such as Mr Ali believe he is Saudi Arabia's main ally in Yemen.
"General al Ahmar is the only force in Yemen that could be accepted by the Saudi regime to rule the country in a way that will not harm Saudi interests. He is Saudi's backup ruler in Yemen," he said.
People who know the general also describe him as a business tycoon with a personal fortune that exceeds President Saleh's.
Ali Almujahed, a political analyst, says: "He is involved indirectly in the biggest oil deals in the country and a percentage of the country's oil revenue goes to him."
The whiff of scandal has trailed General al Ahmar's business dealings. Even his supporters do not deny that he has been involved in some of the biggest corruption scandals in the country in recent years.
General al Ahmar is considered a "major beneficiary of diesel smuggling", according to a western diplomat in Sana'a, who spoke on condition of anonymity. Economists and analysts place the value of the diesel fuel smuggling business here at up to US$10 billion (Dh36.7bn) annually. With his considerable personal wealth, the general has created a vast patronage network, funding tribal leaders, politicians, businessmen and media outlets.
Zaid Thari, a political analyst, said: "Tens of thousands of people receive salaries from him directly, and within the presidential palace, there are tens of senior security officials who receive monthly salaries from him and listen to his commands."
General al Ahmar was born in 1945 in the village of Bait al Ahmar, near Sana'a, and raised in a conservative religious family. He received his bachelor's degree in 1974, majoring in military sciences, and did doctoral studies at the Nasser Supreme Military Academy in Cairo in 1986.
His relationship with Mr Saleh began to sour several years ago over rivalries with two of the president's sons, both commanders of key Yemeni military units. According to one account, contained in a US diplomatic cable leaked to WikiLeaks, Mr Saleh tried to kill General al Ahmar in 2009 by telling Saudi Arabian forces that a home belonging to him was a hideout for Houthi insurgents.
Mohammed Khaberi, a military affairs expert, said: "No one can forget the person who tried to kill him, but al Ahmar waited long to demand that Saleh step down. We wouldn't be surprised if Mohsen comes up with a plan to handicap Saleh and forces him to step down within days."