Nicknamed "the Crocodile" for his ruthlessness, Emmerson Mnangagwa who will take over as Zimbabwe's next president, is a hardliner with ties to the military who could prove as authoritarian as his mentor Robert Mugabe.
It was his political ambition to take over which set off a bitter succession battle between him and Grace, the president's 52-year-old wife, triggering the crisis that toppled the autocrat, who resigned on Tuesday.
When Mnangagwa was dismissed as vice president by Mugabe on November 6, it initially looked like he'd been outfoxed by the first lady, forcing him to flee the country.
But the situation quickly turned on its head, with his dismissal triggering a military takeover and mass street protests, which ended with Mugabe's ouster and Mnangagwa catapulted to centre stage.
With the nation still reeling from Mugabe's lightning demise, the 75-year-old was to make a triumphant return home on Wednesday and be sworn in as president on Friday.
A former close Mugabe ally, Mnangagwa's fall from grace appears to have been engineered by the first lady, who lobbied her husband to back her own political ambitions.
It was the climax of a long feud between the pair over who would replace the ailing and increasingly frail 93-year-old leader.
But Mnangagwa's dismissal alarmed the army, with the generals quickly moving in, staging a military takeover which brought him down within days.
Mnangagwa's rise to the top comes after decades of experience under Mugabe since Zimbabwe won independence from Britain in 1980.
In the early days, Mugabe appointed Mnangagwa, a young trainee lawyer, as Zimbabwe's first minister for national security.
After that, he held a host of different cabinet positions - but relations between him and his political mentor were not always easy, and the younger man was no stranger to presidential purges.
In 2004, he lost his post as administrative secretary in the ruling ZANU-PF after being accused of openly angling for the post of vice president.
Violence and intimidation
But it was during the 2008 elections that his fortunes really began to change when he was serving as head of Mugabe's election campaign.
Mugabe lost the first round vote, and Mnangagwa allegedly supervised the wave of violence and intimidation that forced the opposition to pull out of the run-off vote.
In the same year, he took over as head of the Joint Operations Command, a committee of security chiefs which was accused by rights groups of organising violence to crush dissent.
He was targeted by EU and US sanctions imposed on Mugabe and his close allies over the elections and the ensuing violence but was promptly handed control of the powerful defence ministry.
A young fighter
Born in the southwestern Zvishavane district on September 15, 1942, Mnangagwa completed his early education in Zimbabwe before his family relocated to neighbouring Zambia.
His grandfather was a traditional leader and his father a political agitator for the repeal of colonial laws that disadvantaged blacks.
In 1966, Mnangagwa joined the struggle for independence from Britain, becoming one of the young combatants who helped direct the war after undergoing training in China and Egypt.
He was arrested and sentenced to death but his sentence was later commuted to 10 years in prison because of his young age.
After independence in 1980, he directed a brutal crackdown on opposition supporters that claimed thousands of lives in the Matabeleland and Midlands provinces.
The Gukurahundi massacres remain the biggest scar on his reputation among many Zimbabweans.
He once remarked that he had been taught to "destroy and kill" - although he later claimed to be a born-again Christian.