Pony-tailed university lecturer Pablo Iglesias has caused a "political earthquake" in Spain, where his left-wing protest party Podemos is catching up with mainstream rivals ahead of next year's general election.
The 36-year-old, who was formally appointed secretary general of the party on Saturday, is the only activist who has managed to harness the anger of Spain's "Indignants" popular protest movement into an influential political force.
His critics brand him a demagogue and say he does not know how to fund his anti-free market policies.
Bearded and modestly dressed with a solemn gaze, Iglesias vows to defend the poor in a country stricken by high unemployment and corruption scandals.
He rails on Twitter and in numerous television interviews against Spain's elite "caste" of mainstream politicians and bankers.
"We have to do away with all politicians' privileges," he said in one of his thousands of Twitter messages. "It is obscene that those who impose public cuts are living it up."
As a political science lecturer at Madrid's prestigious Complutense University, Iglesias is well-drilled in articulating his message.
"He has lots of self-control. In an argument, he stays calm," said Fernando Vallespin, another political scientist at Complutense.
Born in a working-class Madrid district, Iglesias was active in the communist youth and the anti-globalisation movement before the Indignants movement erupted in 2011.
"He has never been ambitious and does not want to use politics for selfish ends like so many others," said Vallespin. "He thinks he can help."
Podemos formed last January. Four months later, it won 1.2 million votes and five seats in elections for the European parliament. It did so with young candidates mostly new to politics and a campaign budget of just €150,000 ($190,000).
Iglesias has won over many ordinary Spaniards hit by the recent economic crisis, but has riled business leaders and the right-wing press.
"When Pablo Iglesias speaks, I hear Fidel Castro," said Leopoldo Fernandez-Pujals, a prominent businessman, blasting the Podemos leader's proposals to nationalise key companies and restructure debt.
He said Iglesias would "sink the country" if he won power.
Conservative newspaper ABC has dismissed Iglesias's political programme as "unachievable".
Regardless, Podemos has surged in opinion polls ahead of next year's general election.
Feeding off anger over corruption and unemployment, it has shaken up the two-party system that has dominated since Spain emerged from dictatorship in the 1970s.
A poll published on November 2 in centre-left newspaper El Pais gave Podemos 27.7 percent support, just ahead of the main opposition Socialists with 26.2 percent. The ruling conservative Popular Party (PP) was third with 20.7 percent.
The newspaper called it a "political earthquake".
As well as promising to tackle corruption, Podemos wants a 35-hour working week, public control over certain sectors of the economy and the lowering of the retirement age to 60.
It has offered to hold a referendum on whether Spain should stay in NATO and vowed to oppose the country's involvement in international conflicts.
But Vallespin warned that Iglesias "has a skill for passing the buck" on delicate issues.
"There will come a time when he can't do that anymore."