In this November 21, 2014 photo, Sri Lankan Health Minister Maithripala Sirisena, (centre), acknowledges the gathering as he arrives for a press briefing in Colombo. (Associated Press photo)
Sri Lanka's Maithripala Sirisena was a low-profile minister until he emerged as the best hope for a fractured opposition to topple South Asia's longest-serving leader, Mahinda Rajapakse.
The 63-year-old has become an unlikely rallying point for disaffected Sri Lankans since he walked out of Rajapakse's government a day after sharing dinner with the strongman president.
He has pledged to abolish the executive presidency within 100 days and return the country to a Westminster-style parliamentary democracy where the police, the judiciary, and the civil service will be independent institutions.
Rajapakse had removed the two-term limit on the presidency and given himself more powers soon after winning a second term in 2010 in what critics say were signs of growing authoritarianism.
"He is a mild-mannered, soft spoken politician," said retired senior civil servant and former colleague Austin Fernando of Sri Lanka's possible next president.
"He is unabrasive. A likeable chap who can easily command respect."
Dressed in the white sarong and tunic favoured by Sri Lankan politicians, Sirisena appeals to a rural electorate while his main backer, the centre-right United National Party (UNP), is more popular in urban areas.
The government accuses him of being a proxy of former president Chandrika Kumaratunga, who came out of retirement to boost his electoral fortunes by asking her loyalists to vote for him.
He says he will make UNP leader and former premier Ranil Wickremesinghe his prime minister if he wins, and together they pose a serious threat to Rajapakse.
Jail FearsIf he fails to oust the president, however, Sirisena believes he could end up in jail.
Former army chief Sarath Fonseka, who mounted a failed bid to challenge Rajapakse in 2010, was jailed for over two and a half years on controversial charges and through an even more contentious legal process.
"I know what happened to General Fonseka can happen to me too," Sirisena repeated at the start of campaign rallies six weeks ago.
The son of a World War II veteran, Sirisena entered parliament in 1989 after settling in the eastern district of Polonnaruwa.
He was a soft target for the Tamil Tiger rebels during the height of fighting and says the separatists may have tried to assassinate him on at least five occasions.
He was jailed for nearly two years after being arrested on suspicion of leading a revolt against the government in 1971 when he was just 20.
After his defection from the government Rajapakse kicked Sirisena out of the Sri Lanka Freedom Party although he insists he is still a member.
His vision for the country ties in closely with the free-market, investor-friendly policies of the opposition UNP which provided him with the political base to challenge Rajapakse.
One of Sirisena's key pledges has been to "end the Rajapakse family rule" - and many voters say they will choose him because of who isn't, not because of who he is.
"What I promise is a political and social transformation," Sirisena said at his final election rally in Colombo on Monday.