The billionaire sultan who rules Malaysia's Johor state was sworn in as the nation's new king Wednesday under a unique rotating monarchy system.

Sultan Ibrahim Iskandar, 65, took his oath of office at the palace and signed the instrument of the proclamation of office in a ceremony witnessed by other royal families, Prime Minister Anwar Ibrahim and Cabinet members. A coronation ceremony will be held later.

One of the richest men in the country, Sultan Ibrahim has an extensive business empire ranging from real estate to telecoms and power plants. The candid monarch has close ties with Anwar and his rule could bolster Anwar's unity government, which faces a strong Islamic opposition.

Nine ethnic Malay state rulers have taken turns as king for five-year terms under the world's only such system since Malaysia gained independence from Britain in 1957. Malaysia has 13 states but only nine have royal families, some that trace their roots to centuries-old Malay kingdoms that were independent states until they were brought together by the British.

Sultan Ibrahim's election to the national throne by his fellow rulers in October was widely expected based on an established rotation order. Sultan Nazrin, the ruler of Perak state and next in line to the throne, was reelected as deputy king.

WHAT IS THE KING'S ROLE?

Known as the Yang Di-Pertuan Agong, or He Who is Made Lord, the king plays a largely ceremonial role, as administrative power is vested in the prime minister and Parliament. The monarch is the nominal head of the government and armed forces, and is highly regarded as the protector of Islam and Malay tradition. All laws, Cabinet appointments and the dissolution of Parliament for general elections require his assent. The king has the power to proclaim an emergency and pardon criminals.

Sultan Ibrahim succeeded Sultan Abdullah Sultan Ahmad Shah of Pahang state, who presided over a tumultuous period that included COVID-19 lockdowns and political instability.

The political influence of the king has grown in recent years. Sultan Abdullah intervened in the past to decide who became prime minister, including naming Anwar as prime minister after 2022 general elections led to a hung parliament.

Sultan Ibrahim has indicated he will maintain a hands-on approach. He said in a media interview last month that he would not want to waste five years on the throne as a “puppet king” but will focus on fighting graft and deepening unity in the country. The sultan and other rulers have also warned against attempts by the opposition to oust Anwar's government, calling instead for political stability.

WHO IS SULTAN IBRAHIM?

Sultan Ibrahim, whose mother is English, is also vocal about welfare issues and takes annual road trips on his motorbike to meet the people in his state.

He has also made no secret of his wealth. Earlier Wednesday, the sultan flew from Johor to Kuala Lumpur on his private jet, a gold -and-blue Boeing 737. Apart from a fleet of jets, he has an extensive collection of cars and motorcycles, as well as properties abroad. Sultan Ibrahim is also the only ruler with a private army — a condition agreed upon for the state to join modern-day Malaysia.

Sultan Ibrahim's high corporate profile — including a stake in the multibillion-dollar Forest City development project in Johor with China's beleaguered developer Country Garden — has raised eyebrows amid concerns of a possible conflict of interest. He has said in the media interview recently that he plans to revive a high-speed rail link project with Singapore and bolster the troubled Forest City project.

But the sultan has defended his business dealings. In 2015, he quipped that he has to “earn a living, like ordinary Malaysians” as he cannot rely on his 27,000 ringgit ($5,700) monthly state allowance.

His wife Raja Zarith Sofiah, who is from another royal family, is an Oxford graduate and a prolific writer who has authored several children's books.