ISIS already has a new leader — a feared former officer for Saddam Hussein known as “the Destroyer,” according to reports.

Abdullah Qardash was reportedly already running day-to-day operations and kill campaigns for the terror group and formally took over its leadership after Abu Bakr al-Baghdadi’s death on Saturday.

“Baghdadi was a figurehead. He was not involved in operations or day-to-day,” a regional intelligence official told Newsweek in confirming the successor. “All Baghdadi did was say yes or no — no planning.”

Qardash had been loyal to Baghdadi after they were held together at the Camp Bucca detention center in Basra after being jailed by US forces over their links to al Qaeda in 2003, the Times of London has said.

Even before his death, Baghdadi was handing more power to Qardash, known as a brutal policymaker whose name is sometimes spelled Kardesh, the Times said.

A former security analyst with the Iraqi government, Fadhel Abo Ragheef, told the paper in August that Baghdadi was understood to be “trying to prepare Qardash to lead ISIS in the future.”

Researchers at the S. Rajaratnam School of International Studies in Singapore also stated that Qardash would be the successor, noting that he was known as both “the Professor” and “the Destroyer.”

“Described by some security analysts as cruel and authoritarian yet popular and well-respected among other IS members, Qardash was responsible for eliminating those who are against al-Baghdadi’s style of leadership,” the researchers said.

The new leadership comes amid fears that Baghdadi’s death may unleash a fresh round of terror campaigns.

“They will hit Syria, the chaos of Iraq, Europe and definitely the United States,” the regional official told Newsweek. “You have hit a sleeping giant, it will wake up and cause unforeseeable chaos and wreak havoc on the Western civilians.”

French Interior Minister Christophe Castaner warned police in a letter of possible calls “for acts of vengeance.”

“Sleeper cells will seek revenge for Baghdadi’s death,” Mazloum Abdi, top commander of the Syrian Democratic Forces, told Agence France-Presse.

The parents of James Foley, the American journalist beheaded by ISIS in 2014, also fear that the leader’s death will not end the terror.

“I believe ISIS is like grass,” Foley’s dad, John Foley, told WMUR-TV. “You mow it, but it continues to grow. And I don’t think that the elimination of al-Baghdadi is the final answer.”

With Post wires