A seasoned diplomat, a cardiologist and a lawyer will represent Syria's two sides at UN-brokered peace talks that begin Thursday in Geneva aimed at ending six years of brutal warfare.
The diplomat, Bashar al-Jaafari, is the Syrian government's veteran envoy at the United Nations: he will square off against opposition figures Nasr al-Hariri, a cardiologist, and lawyer Mohammad Sabra.
Here are mini-profiles of the three men:
Jaafari: worldly-wise diplomat
The 61-year-old Jaafari has for years been the fiercest defender of the Syrian government, even more so since the start of the conflict in March 2011.
The tall and silver-haired diplomat has unequivocally and with a sharp tongue denied time and again a multitude of accusations levelled by international bodies against the Damascus regime.
Syria's government has been accused of flouting human rights time and again and of using banned chemical weapons on the battlefield against its opponents -- charges flatly rejected by Jaafari.
"His myopic and unquestioning analysis of the situation in Syria makes him difficult to engage with and ineffective as an interlocutor," a UN Security Council diplomat has said of Jaafari .
"His argumentative performances in the Council do little to challenge the perception that he is less of a diplomat and more of a loudspeaker" for Syrian President Bashar al-Assad.
Born in 1956, Jaafari, who is married to an Iranian, hails from Damascus and belongs to the same Alawite religious minority as Assad. 1
Then Secretary-General of the Syrian National Coalition Nasr al-Hariri (C) leaves a meeting with veteran opposition figure Haitham al-Maleh and Arab League Secretary-General, Nabil al-Arabi, in Cairo on September 6, 2014 (photo by: Mohamed EL-SHAHED/AFP/File)
He wears his thin glasses low on his slender nose, has a neatly trimmed goatee and is seldom seen smiling.
Jaafari holds degrees in French literature and translation, a doctorate in political sciences from the Sorbonne University in Paris and is fluent in English and Farsi, in addition to his native Arabic.
His first diplomatic posting was to Paris, later moving to positions in New York and Indonesia. Since 2006, he has been Syria's permanent envoy to the United Nations.
"He's a ruthless negotiator, and he understands very well what happens backstage at the UN," a journalist with years of experience in Damascus has told AFP.
"People in Damascus have nicknamed him 'the lion of diplomacy'," he said, a nod to Assad whose name means lion in Arabic.
Jaafari prefers to speak in classical Arabic, using ornate language which translators have often found difficult to render into English.
Hariri: diplomat cardiologist
The High Negotiations Committee (HNC), which has emerged as the leading umbrella group for Syria's opposition factions, has opted for non-military figures to represent it at Geneva.
One is Hariri, the delegation head who will make his debut on the political and diplomatic stage, while the other is Sabra who has already taken part in talks in 2014 and 2016.
The 40-year-old doctor specialised in cardiology.
He comes from Daraa, the cradle of the Syrian uprising where the first protests erupted in mid-March 2011.
The start of the conflict -- which has now killed more than 310,000 people and forced millions from their homes -- was a turning point for Hariri.
After practising in both Daraa and Damascus, he was thrust from the onset of the conflict into relief work and then joined the opposition National Coalition.
Like Jaafari, he is fluent in English. But this is where the similarities end, and confronting the seasoned diplomat could be tough, sources close to Hariri say.
Hariri "is not easily provoked. He is a cardiologist and cardiologists know how to be calm and cope with pressure," one source said.
A National Coalition figure who was worked with Hariri calls him "a good negotiator who is sharp and eloquent".
An activist who has also served with him says Hariri "is very diplomatic but at times he can explode".
Sabra: savvy lawyer
Sabra is a tough and experienced lawyer who will be the HNC's chief negotiator and Jaafari's opposite number.
He takes over from Mohammed Alloush, from the Jaish al-Islam powerful rebel faction, who represented the opposition at the last round of talks in March last year.
In 2014, Sabra was on a technical team that joined peace negotiations in Switzerland and last year he was also a negotiator in the opposition team that went to Geneva with Alloush.
As legal adviser to previous delegations, Sabra knows his subject inside out.
He has worked closely with the National Council, drafting and editing several legal documents for the opposition body.
Towards the end of 2014, Sabra quit the National Coalition and co-founded the opposition Jumhurriya party.
Sabra, who is based in the United Arab Emirates, has kept a low profile over t he years, but colleagues praise him as an academic.
He has a masters in private and corporate law.