Abdullah Ocalan, the leader of the Kurdistan Workers' Party (PKK), was banished to his island prison 14 years ago, narrowly escaping the gallows.
Greyer and tempered by long isolation, he now braves the scepticism of many Turks, and some of his own fighters, to don the mantle of peacemaker.
Long reviled in much of the Turkish media as a "monster," Ocalan ordered his fighters on Thursday to withdraw to the mountains of northern Iraq and cease fighting, his words read to hundreds of thousands of Kurds gathered in the regional city of Diyarbakir.
In scenes unthinkable over the past 28 years of conflict, the banned image of the moustachioed fighter, now avowedly peacemaker, was borne on placards through the streets amid a sea of red-yellow-green Kurdish flags. Police were nowhere to be seen.
It was a remarkable transformation from the dazed figure, bundled, handcuffed and blindfolded onto a jet by Turkish special forces after his 1999 capture in Kenya. Sitting months later in a bullet-proof glass box at his trial, he had acted more the bargaining statesman than a man fighting for his life.
"If permission is granted, I say I can bring all the men [fighters] down from the mountains within three months," he told the court. "I might not be worth a dime, but they say ... 5,000 suicide bombers are ready to die for me."
The government was ill-inclined at the time to take him at his word. Now, his ability to control his fighters, and Prime Minister Recep Tayyip Erdogan's capacity to rally the support of a conservative establishment, will be put to a test of fire.
There is still a strong nationalist strain in Turkey that rejects any deal with the prisoner of Imrali island and the PKK as verging on treason.
Erdogan, like Ocalan, is taking risks in publicly pursuing talks with a group classified by the EU and the US as well as his own country as terrorist.
Erdogan took the 'Kurdish Question' in hand in a way no government had before him, making concessions on cultural rights and language. As fighting continued, reaching new heights last summer, both sides still looked for a deal.
Sceptics fear any agreement with Ocalan could lead ultimately to an independent Kurdistan and collapse of the economically resurgent Turkey they see now as a growing force in the region.
After years of brooding introspection, 63-year-old Ocalan, known to allies as "Apo", appears to have assumed the role he long claimed.
"If we are successful there will be a totally new republic ... radical democracy," Ocalan told pro-Kurdish politicians visiting him on Imrali near Istanbul last month.
Ocalan's comments portray a man who sees himself as a key figure in shaping a new Turkish democracy, a role Erdogan has claimed for himself, not least in his taming of a military establishment that would balk at dealings with the PKK.
"There will be no need for house arrest or an amnesty. We will all be free," the PKK leader said, referring to himself and the thousand of his fighters fighting in the mountains, as well Kurdish activists jailed in Turkey.
Certainly the release from jail of such a controversial figure as Ocalan, something that would have to be considered as a peace process continues, would be a risk for Erdogan.
The years have seen a stark evolution of Ocalan's thinking, with belief in armed insurrection to achieve an independent state giving way to a focus on democratic reform to meet Kurdish cultural and political demands.
"He has evolved to such an extent that let alone an independent Kurdish state, he doesn't even want to refer to 'democratic autonomy'," said Eyup Can, editor of the liberal Radikalnewspaper, which has followed the talks closely.
Some argue the roots of Ocalan's violent rebellion lie in a tough childhood in the village of Omerli, in southeast Turkey's Sanliurfa province.
An overbearing Turkish mother, a weak father, a home "without much family love or discipline" seem to have forged a contradictory character.
"My passion was to roam the mountains," he said at a televised trial that gripped Turkey. "The villagers knew me both as someone who wouldn't hurt a fly and as a snake hunter".
Successful at school, Ocalan went on to study at university in Ankara where he first became active in left-wing politics, developing the ideas which would come to fruition with the foundation of his Marxist PKK in 1978. He launched the group's armed struggle in 1984.
Before his capture, Ocalan, the dominant and unrivalled leader of the PKK, was based in Syria. His security there was shattered in 1998 when Turkey threatened armed action against Syria if he was not handed over. Ocalan fled.
Then followed a race across Europe in search of asylum, flying between Greece, Russia and Italy before Turkish special forces seized him in Kenya on February 15, 1999, reportedly with the help of US, or Israeli, security services.
As the plane flew over Egypt, the pyramids visible through the window, he looked resigned and weary, smiling at times with his masked captors.
Condemned to hang for treason, his sentence was commuted to life in jail after Turkey scrapped the death penalty in pursuit of EU entry. Ocalan though retained influence among fighters and activists in Europe as a symbolic figure.
Isolation may have taken its toll on Ocalan, who complained last month in talks with Kurdish politicians about a pessimism in PKK ranks over the talks. "I'm angry with them," he said, voicing criticism of their "war system".
Even last week, PKK commander Murat Karayilan spoke of "several concerns and problems that need to be overcome," without elaborating.
"This process has got the best set of circumstances we have seen in a decade," said Hugh Pope, Turkey project director for the International Crisis Group.
"The right people are in the room, two principals that can deliver a deal. The Kurdish movement is open to a settlement and Ocalan seems by all his actions to be genuinely wishing to strike a deal now."
Mainstream media, which appear largely to support the process, has tried to soften Ocalan's image and have largely dropped descriptions of him as the "terrorist chieftain".
Deputy Prime Minister Bulent Arinc has described Ocalan as "an important actor" who could play a positive role.
Wary of triggering a nationalist backlash, Erdogan himself keeps his distance and avoids using Ocalan's name.
Instead he refers to him as "Imrali" and vows to keep up the fight against Ocalan's rebels until they lay down their weapons.
If a deal is done, the fighter-turned-statesman might yet walk free as a politician of influence. If peace holds, his adversary Erdogan can claim an achievement that before his election seemed scarcely possible.