A man walks into a bar. Normally, that means a punchline is coming. But funny things seldom happen when Mr Rodrigo Duterte - former mayor of Davao city, and the latest candidate to throw his hat in the Philippines' often rambunctious presidential derbies - walks into a bar. More likely, it means a punch is coming.

One story goes like this. A tourist at a bar who had too much to drink refused to follow Davao's anti-smoking law, one that Mr Duterte considers a legacy. When told repeatedly that it was against the law to smoke indoors, the man blurted: "On whose orders? Duterte's not paying for my cigarettes!"

Moments later, Mr Duterte walked into the bar, sat beside the flabbergasted tourist, pulled out the .38 revolver he always has tucked in his waistband, pointed it at the man's crotch, and told him to choose: "Your manhood, or you swallow your cigarette butt."

The man walked out of the bar with his manhood intact.

With his larger-than-life persona, outlandish and often expletives-laden take on life and politics, and almost single-minded agenda to rid the Philippines of criminals by any means necessary, the 70-year-old Mr Duterte stands out among the other presidential wannabes.

"The message of Mayor Duterte is law and order… running after the guilty, and that certainly resonates with a lot of people, including myself," House Speaker Feliciano Belmonte said.

In the crime-weary capital Manila, he topped a poll conducted two weeks ago, with one in three of the respondents saying they would vote for him for president.

Mr Duterte is running in a field that, until now, has had no breakaway leader.

Senator Grace Poe, 47, daughter of a former movie icon, leads the pack. Nipping at her heels are Vice-President Jejomar Binay, 73, and former interior minister Mar Roxas, 58, President Benigno Aquino's choice to succeed him.

A fifth candidate, Senator Miriam Santiago, 70, is bringing up the rear.

Nationwide, Mr Duterte is tied in third with Mr Roxas.

His big advantage, though, is that, while the other candidates have been fuzzy about their political platforms, he is crystal clear about what he will do.

He is already assuring funeral parlours of brisk business if he wins.

"If I become president, I advise you people to put up several funeral parlour businesses because I am against illegal drugs… I might kill someone because of it," he said last week.

Although heavy on hyperboles, this is not idle talk.

Mr Duterte has been credited with transforming Davao from being "murder capital of the Philippines" to one of the country's safest and most orderly cities.

How he did it, however, is shaping much of the talk about whether he is what the Philippines needs to sustain the period of robust growth set in motion by Mr Aquino.

When he was appointed officer in charge of Davao in 1986, Mr Duterte set off by ending a bloody war in the city between anti-communist militias and leftist partisans. For 22 years, he presided over a ruthless anti-crime campaign that earned him the titles "The Punisher" and "Duterte Harry". This is a play on the "Dirty Harry" detective movies starring Clint Eastwood.

In one particularly bizarre episode in 2012, he offered a two million-peso (S$60,000) reward for anyone who could bring him the severed head of a known leader of a gang of car thieves.

Mr Duterte has confessed publicly that he has ties with "death squads" accused of murdering more than 1,000 suspected criminals.

Human-rights advocates have been pushing to hold Mr Duterte responsible for these summary executions. But as far as Mr Duterte is concerned, it makes for a good campaign pitch.

Addressing criminals, he said in one TV interview: "I do not want to commit a crime but, if by chance, God will place me there, you all better watch out. That 1,000 will become 100,000. I'll dump all of you into Manila Bay, and fatten all the fish there."

All this bluster is in line with the image he has been cultivating all his life.

The son of a former governor, Mr Duterte was a street-smart thug in his teens. At 14, he flew a plane over his school to throw rocks at it after the dean gave him a public scolding. But he did grow out of his mean streak, managed to get a law degree, and then a job as prosecutor.

In public, his life seems to follow the script of a B-rated action movie.

He has been seen patrolling his city on a Harley-Davidson. At night, he prowls the streets incognito as a cab driver.

He also has a reputation as a ladies' man, with at least two women in his life.

He was married to Ms Elizabeth Zimmerman, a former flight attendant, for 27 years. They have three children, all adults now.

He now lives with a new partner, Ms Honeylet Avencena, a nurse, with whom he has an 11-year-old daughter.

For Mr Danilo Mariano, a political analyst, columnist and human-rights victim under the Marcos regime, voters will have to cut through the hype.

"I have been warning my friends, who are looking forward to a Duterte presidency, be careful what you wish for," he said.