Is he Zimbabwe's future president?

Mysterious. Dangerous. Reclusive. Hardline. Ruthless. Rich and helpful. All of these descriptions have been used for 72-year-old Emmerson Mnangagwa.

Sworn into office as vice-president on Friday, Mnangagwa has said little in public other than to pledge loyalty to President Robert Mugabe and vow that he will crush political opponents. In the reshuffled cabinet, he keeps his justice portfolio, while filling the largely ceremonial post of vice-president.

His fellow vice-president, Phelekezela Mphoko, a career diplomat, was arrested 30 years ago during the crackdown on the then-opposition Zapu. Most Zimbabweans know little about Mnangagwa and even less about Mphoko.

All things remaining equal, Mnangagwa will succeed Mugabe, 90; not least because the old man feels comfortable with his new deputy, and has trusted him for decades.

Mphoko's appointment is a sop to the few surviving members of Zapu who entered a unity accord with Zanu-PF in 1987 after many members of the party were killed in the early years of independence.

Mnangagwa's appointment is significant, as it's the first time that Mugabe's put a successor in place.

Had Mugabe not been under obligation to the military, which supported his becoming leader of Zanu in 1977, and to the late General Solomon Mujuru in particular, Mnangagwa would probably have become Mugabe's deputy 10 years ago.

Mujuru worked the ropes in Zanu-PF, and the party's constitution was changed to ensure that a woman was in the "presidium". This led to his wife, Joice's rise to the post in 2004.

Mnangagwa was outraged. He detested Solomon Mujuru.

Mugabe changed the Zanu-PF constitution earlier this month to scrap party elections. He then appointed Mnangagwa and others to the Zanu-PF hierarchy. The emergence of Mnangagwa last week as Mugabe's chosen successor should not surprise anyone.

He's had personal profitable relationships with some of Zimbabwe's richest businessmen, among them tobacco merchant and arms dealer John Bredenkamp, super-rich businessman Billy Rautebach and a number of official and back-street gold dealers, some of whom were in and out of police cells for several years. Insiders in the mining sector say Mnangagwa is key to ensuring certain coal exploration contracts are eased through the system.

Mnangagwa controlled the clutch of companies that Zanu-PF built during the 1980s. When these were investigated by the party 10 years ago, it was found most had failed miserably. Rather like Zanu-PF's economic performance. Mnangagwa, of course, like Mugabe, says US and EU travel and personal financial restrictions, imposed after 2002 on Zanu-PF leaders, are responsible for the decline. The EU has lifted all but those on Mugabe and his wife, Grace. Mnangagwa was state security minister for the first eight years of Zimbabwe independence, so he cannot escape accusations that he played a leading role in the atrocities against Zapu leader Joshua Nkomo's supporters, most of whom were from Matabeleland.

When challenged about detentions in the turbulent 1980s, he often blamed the then-minister of home affairs. He says that the army was responsible for the era's violence.

According to Judith Todd's Through the Darkness, the only book that charts much of Zimbabwe's political history since independence in 1980, he was helpful, from time to time, in ensuring some of the detainees from the post-independence era were released. Most of these detainees were liberation war heroes. He knew them; had fought with them. But they were Zapu.

He has said often: "Those who fear me are not honest people."

One of his allies, Zanu-PF MP Joram Gumbo, told the BBC this week that the new vice-president was"misunderstood by many".

"If you get to understand him, you will soon discover he is a down-to-earth person."

As justice minister, Mnangagwa, a lawyer, refused to sign death warrants for 97 murder convicts this year, saying the "sentence is too harsh and must be done away with".

When he was captured and tried during the Rhodesian war, Mnangagwa escaped the gallows because the court deemed him too young to be hanged.

"I assured the president - I want to assure the party; its leadership - that I will remain loyal, committed, and will deliver the correct line of the revolution," he told reporters after his appointment.

This means protecting the first family's assets after Mugabe dies. First Lady Grace Mugabe's entrance into politics in August was key to his success as it was she who launched, in public, an outrageous campaign against Joice Mujuru.

Optimists in business think Mnangagwa will make life easier for investors brave enough to consider Zimbabwe. His ally, Finance Minister Patrick Chinamasa, is also hoping Mnangagwa will make a difference. He told parliament during his budget speech last month that more than 80 percent of state revenue was going to public sector wages.

The eight new cabinet ministers and a couple of new deputies sworn into office have each served in some capacity in the past few years. They are in the same mould as those who have been in power since 1980, so change is unlikely.

Only one or two of the cabinet changes are key to the economy: the energy and power development portfolio was taken from the Mujuru camp appointee and awarded to Sam Udenge, who has a sparse public service success record and who was taken to court a few years ago for failing to pay for his children's education.

Long-standing minister Olivia Muchena, seen as loyal to Mujuru, was replaced by Oppah Muchinguri, long-time party hack and former girlfriend of Robert Mugabe, who stood aside from her women's league post so Grace could become Zanu-PF secretary for women's affairs. She is now head of tertiary education.

Augustine Chihuri, a Mujuru loyalist who did nothing to stop the abuse of power by the police, was not offered a new contract as police chief. He is expected to be replaced by an appointee from the army.

Webster Shamu, who was minister of communications, has been replaced by former Zimbabwean state and SABC reporter Supa Mandiwanzira, a party loyalist who was awarded a licence for a radio station during the time that Zanu-PF and the Movement for Democratic Change shared power.

If all Mujuru loyalists are to be axed, then there are several more who would get the chop, but Zanu-PF insiders think Mugabe will not go much further with his purge.

Mugabe has not yet appointed a minister for women's affairs, and many wonder whether Grace will get the national post that would complement her role in Zanu-PF.

Including the provincial ministers, who have enormous powers without any infrastructure, there are about 50 ministers and deputies.

The one to watch is Local Government Minister Ignatius Chombo, who has enormous wealth, mainly through seized land.

He is in a key position in Zanu-PF as its administrative secretary, a powerful position since the party's chairmanship was abolished earlier this month.

Simon Khaya Moyo, the former chairman, is the party's new information secretary and spokesman.

Joice Mujuru, her political career over, will receive - for life - the salary and all perks that came with her vice-president's job.