The path to the US-Taliban deal came down largely to two Afghan men - one working for the US, the other for the militants, their lives shaped by decades of conflict.

On one side was Zalmay Khalilzad - a leading US diplomat who spent the prime of his career attempting to restore order as an envoy in Afghanistan and Iraq following successive US invasions.

Across the table was Mullah Baradar, the seasoned jihadist who spent most of his life as a fighter, first with the mujahideen during the anti-Soviet jihad and again as the Taliban's co-founder.

More than 18 years after being toppled from power, it appears Baradar and the Taliban - with Khalilzad's help - are again on the verge of returning to Kabul as arguably the most united force in Afghanistan's chaotic political arena.

Here's a quick look at the two men:

He was also seen as having heavy influence over Afghan President Hamid Karzai, shepherding him through the 2005 elections, while being criticised for cutting deals with brutal warlords.

Following Afghanistan, Bush tapped Khalilzad to serve as ambassador in Iraq as US forces struggled to prevent sectarian civil war while fighting a sprawling insurgency.

After the Bush years, Khalilzad became a harsh critic of President Barack Obama's handling of the Afghanistan war as well as the Pakistan's alleged support to the Taliban.

In 2018, Khalilzad was again hand-picked to patch up things in Afghanistan, this time by President Donald Trump to lead negotiations with the Taliban.

The process has not gone without criticism, particularly for sidelining Afghan President Ashraf Ghani's administration, sparking comparisons to the Americans' withdrawal from Vietnam in the 1970s.

- Baradar, the fighter -

Abdul Ghani Baradar was born in the arid badlands of southern Afghanistan's Uruzgan province and later raised in Kandahar - the future birthplace of the Taliban movement.

Like most Afghans, Baradar's life was forever altered by the Soviet invasion of the country in the late 1970s, transforming him into an insurgent believed to have fought side-by-side with the one-eyed cleric Mullah Omar.

The two would go on to found the Taliban movement in the early 1990s amid the chaos and corruption of the civil war that erupted after the Soviet withdrawal.

The Taliban eventually seized the southern capital of Kandahar almost without a fight before capturing Kabul in 1996 and installing a hardline Islamist regime.

Following the Taliban's collapse in 2001, Baradar is believed to have been among a small group of insurgents who approached interim leader Hamid Karzai - who hails from the same tribe - with a letter outlining a potential deal that would have seen the militants recognise the new administration.

The reconciliation efforts failed and Baradar is believed to have returned to the battlefield, where his experience as a military commander and strategist likely helped rebuild the Taliban.

Arrested in Pakistan in 2010, Baradar was kept in custody until pressure from Khalilzad saw him freed in 2018 and relocate to Qatar where he was appointed head of the Taliban's political office in Doha in January.

Baradar is believed to be widely respected by the Taliban's various factions and experts say his presence would help garner support for any deal from insurgents on the frontlines.