Mr Otegi, 40, heads his party's list for leader of the autonomous parliament, and is the first Herri Batasuna (HB) leader to be given public prominence. This marks a change of tack for an outfit that has traditionally taken a perverse pride in its grim-faced and anoraked collective leadership.
Granted, he still wears jeans and the obligatory woolly jumper, and bounds to the front of election rallies with the clenched-fist salute. But in addition to the usual high-energy rant against the evils of Madrid, he smiles. Occasionally he makes jokes. And, most importantly of all, in a region where feelings of hope and relief have blossomed since the separatist movement called a truce on 18 September, he is ready to sit down and talk.
"I'm proud to be compared with Gerry Adams," he said in a recent interview. "We have looked at the Irish mirror and we will continue to do so. It is an inspiration for peace."
Rallies in the election, in which the party is campaigning as Basque Citizens, are awash with green banners in homage.
HB has staged its biggest show of strength in its heartland of San Sebastian, with thousands packing into a vast sports hall for a passionate celebration of Basque-ness. Fiery speeches were interspersed with high-kicking dancers, pipers and the traditional singing poets, the bertsolari, who intoned the names of imprisoned comrades in a lament that stirred the heart.
For one long moment Eta's banner, with its sinister hatchet and serpent symbol, fluttered from the rafters. But the biggest applause greeted relatives calling for an amnesty for hundreds of Eta prisoners held throughout Spain.
Crumpled, careworn men and women crowded on to the platform, each bearing a photo of a son or brother held in a distant jail. The spectacle of that dense forest of monochrome mugshots brought cries, songs - even keening - from thousands of throats. Bringing home the prisoners is HB's priority, and Mr Otegi knows the government is preparing concessions, but via talks and not the gun.
Mr Otegi may be recycling himself as the human face of Basque separatism but his long career as an Eta hardliner is what gives him clout. One of the organisation's secretive inner core, he was in jail in Spain and France from 1987 to 1993 for terrorist offences. He was held responsible for four kidnappings, an assassination attempt on a Spanish conservative leader, an assault on a military barracks in San Sebastian, hijackings, bomb attacks and the theft of arms and dynamite.
A father of two, philosophy graduate and skillful debater and public speaker, Mr Otegi is already a member of the Basque parliament. Like all HB members, he turns up only sporadically. Virtually unknown a year ago, he emerged into the limelight after the entire 25-strong HB leadership was jailed last December. They were convicted of collaborating with terrorists after distributing a pro-Eta video during the 1997 election campaign.
He became interim leader pending the election of a new executive committee. But despite the hardline reputation of those jailed, they had already agreed on a softer approach, following popular revulsion over the kidnap and murder in July last year of the young conservative councillor, Miguel Angel Blanco.
In March Mr Otegi still thought an Eta ceasefire was a remote possibility. But he was convinced of the need to talk to the moderate Basque Nationalist Party (known by the Spanish acronym, PNV) to break HB's isolation and explore the prospect of wider talks for peace.
"It made more sense to work things out amongst ourselves than talk to the PP [Popular Party] government in Madrid," he said. "We don't want the suffering to go on, and we want allies."
His courtship of the PNV deliberately echoed Sinn Fein's rapprochement with John Hume, the SDLP's leader, and marked a turning point. Mr Otegi used his credentials as a former gunman to guarantee that Eta would not torpedo the talks. Eta's truce "is a serious attempt to bring Basque society to a definitive solution of the conflict", he said last week.
"Whatever the result of [today's] election, it will not affect Eta's decision to maintain the ceasefire. We will scrupulously respect what Basques decide." What is the betting that Mr Otegi could soon be sitting round a table with ministers from Madrid?Reuse content