His friends call him "The Wrath of God," his enemies "The Cat Killer," but all Iranians regard Sadegh Khalkhali as a man to be reckoned with.

The chief of Iran's revolutionary court system, known for his death sentences, Khalkhali is a short, squat man, convinced that vengeance is a religious duty and determined to seek revenge among the "corrupt on earth," both in Iran and abroad.

His sometimes outwardly vainglorious boasts about assassinating shah Mohammad Reza Pahlavi, his family and chief lieutenants are being taken seriously since the recent assassination in Paris of a son of the deposed monarch's twin sister, Princess Ashraf.

"I don't think I have made any mistakes," he said today when asked if it was true he had erred in some of his execution orders.

A perhaps apocryphal story recounts that when told he had ordered the execution of a man whose identity had been mistaken for that of a genuine suspect he replied: "No matter, in any case he will go straight to heaven."

Khalkhali's detractors recount a legend that Khalkhali's lifelong penchant for torturing and killing cats reached such proportions that he had to be interned for treatment in a mental institution in years past.

As the 53-year-old Moslem cleric tells it, his life under the shah was an unending persecution: first in prison for siding with his exiled teacher and hero, Ayatollah Ruhollah Khomeini, then in banishment in a variety of unattractive provincial towns.

He has no doubts about his present calling. He recounted today that when he told Khomeini he was being asked to accept a "heavy responsibility" in running Iran's revolutionary courts, Khomeini replied, "I think you are not afraid."

Armed guards patrol outside his modest house near the railroad tracks in this holy city and visitors are frisked before they are admitted into the courtyard where the washing hangs on the line.

Inside, stony-eyed acolytes sitting on rugs follow an exuberant Khalkhali's every utterance as their leader interrupts his interview to deal with favor seekers and stamp proffered documents with a copper chop.

He appears proud of his controversial reputation and boasts of "anonymous letters and telephone calls" threatening his life.

"I was also threatened by the government and revolutionary council," he said cryptically.

Nor is Khalkhali bashful in conceding such opposition within the government to his penchant for executions.

"I've ordered more than 200 executions," he said laughingly, "more than the Nuremberg trials" of Nazi war criminals after World War II. Other sources put the number of executions since the February revolution at more than 600, although some no doubt were not condoned or ordered by him.

He specifically mentioned then-prime minister Mehdi Bazargan's opposition to the executions last spring of the shah's longtime prime minister, Amir Abbas Hoveyda, the former director of the SAVAK secret police, Nematollah Nassiri, and an earlier SAVAK boss.

Bazargan argued that Hoveyda and Nassiri were entitled to a fair trail during which the shah's alleged crimes could be exposed -- a view that Khomeini has adopted in the present hostage crisis with the United States by calling for a show trail to establish U.S. guilt.

Khalkhali defended his decisions, arguing that with their connections and money "They'd be freed by now" had he not had them shot.

"If Nassiri came back to life," he said, "I'd kill him again.'

Perhaps oddly for a man with such decidedly rigid views, he said he hoped for the freedom of the 50 Americans held hostage at the U.S. Embassy, whom he referred to as "our guests."

However, he said he hopes "none will be executed," although that might be possible "if some are found guilty of ordering shooting of people."

But he seemed as interested in a trial of "all presidents from Carter back to Roosevelt," the current government approach, which insists that the United States has been responsible for all Iran's woes under the shah.

"The shah called his book "Mission For My Country'," Khalkhali said, "and I want to know who was responsible for that mission."

Carefully calculating his effect on a roomful of admirers, he took issue with Carter's decision not to light all the White House Christmas tree lights until all the hostages were freed.

"How come he didn't do the same thing during the Vietnam war when so many people were killed or last year when so many Iranians died fighting the shah," he asked." If Carter wants to deceive people, the hostages will not be freed for 10 years."

Slurping tea from a saucer, cracking his pudgey knuckles and raising his voice, he refused to say how many killer squads were abroad tracking down the revolution's quarry.

"They're trained by the Palestinians," he said. "And in Europe and even America, they are fluent in English and French. And if they find any of the past regime's officials they will kill them."

In addition to the imperial family, he listed as potential victims former prime ministers Shahpour Bakhtiar, Jamshid Amouzegar, Jaafar Sharif Emami, former generals Gholam Ali Oveissi and Gholam Reza Azhari and Hushang Ansary, former head of the National Iranian Oil Company.

Was it not time to stop the revenge, he was asked. "No, he replied, "not yet. I'll give a reward to anyone who shoots someone on the list."

He insisted on his determination to "take my revenge in the name of all the oppressed who suffered during the shah."

Khalkhali seemed ill at ease only when questioned about his controversial role in the revolutionary government's unsuccessful efforts to suppress an uprising by the Kurds in favor of autonomy.

The Kurds accuse him of the wholesale slaughter last summer of civilian innocents at Paveh, Saqqez and Mahabad, including cases such as the executions of a Kurdish doctor and a merchant who refused to abandon his faith and convert to Islam.

These very excesses and errors have branded Khalkhali to such a point that Kurdistan Democratic Party leader Abdurahman Qassemlu recently joked when asked why he had not ordered his assassination.

"Politically," the Kurdish leader asked, "do you think Khalkhali really hurts us?"