In the riddle that is Thai politics, retired major general Chamlong Srimuang is the enigma at its core.
Decades of political struggle have not slowed Mr Chamlong, about to turn 73 next weekend, as he helps lead the thousands of protesters besieging Government House in Bangkok. With characteristic stubbornness, his People's Alliance for Democracy movement - comprising academics, royalists and businessmen - has vowed to force the collapse of an elected government dominated by the political proxies of former prime minister Thaksin Shinawatra.
The billionaire tycoon, Mr Chamlong's one-time protege, was ousted in a military coup in 2006. The putsch - Thailand's first military intervention in more than 15 years - followed months of protests, also led in part by Mr Chamlong.
Thaksin remains banned from politics, insists he is not interested in further involvement and legal action stemming from his five-year rule is continuing - yet Mr Chamlong is taking no chances. With a disparate array of opposition forces, Mr Chamlong fears for Thailand's future unless Thaksin's grip on power is removed for good.
But unlike some of his peers, he is marked by a singular determination and a considerable track record of forcing results, often amid controversy. He is also defined by the austerity of the breakaway Buddhist sect, Santi Asoke, which he champions. Surrounded on the protest hustings by devotees dressed in stylised traditional farmers' garb, Mr Chamlong sports a severe crew cut and keeps to the celibate and vegetarian precepts of his sect.
The austerity extends to his political style. He says little other than reinforcing his core message. 'We will win,' he repeatedly tells his acolytes. He is not given to detailed pronouncements or policy debates. Prime Minister Samak Sundaravej, head of the Thaksin-allied People Power Party (PPP), must 'leave office'.