Mojtaba Khamenei, who has spent his career behind the scenes and is yet to appear in public as Iran's new supreme leader, faces the formidable challenge of occupying the role held by his father for most of the regime's existence.
Iranians knew little about the younger Khamenei when he was named to the lifetime post shortly after a US-Israeli airstrike killed his father Ali Khamenei, supreme leader since 1989, at the start of the Middle East war.
Said to have been wounded himself, Mojtaba Khamenei has issued over dozen written messages as leader that have carried on his father's confrontational ideology, taking aim at Israel and the United States.
In one of his most significant recent interventions, released on June 18, Mojtaba Khamenei said he had given his blessing to talks with the US to end the war despite having a "different view", likely an attempt to stay above the domestic political fray.
Despite the messages and activity on social media channels, there has been no concrete proof that Mojtaba Khamenei is even alive after the February 28 attack that also killed his wife Zahra Haddad Adel and other members of the Khamenei family.
But several Iranian officials have said he was wounded, sparking speculation he could be waiting to recover fully before appearing in public, as well as being mindful of his own security.
With Ali Khamenei's funeral starting Saturday, there will be intense scrutiny for signs of Mojtaba Khamenei emerging, and questions will mount if he fails to appear.
-'Radical' agenda -
Unlike Ali Khamenei, a prominent opponent of the shah who was president in the first decade of the republic from 1981-1989 before becoming supreme leader, Mojtaba Khamenei has never held a government position before.
But observers believe he was second-in-command at the office of the supreme leader under the veteran chief gatekeeper Mohammad Golpayegani.
He is also seen as close to the leadership of the powerful Revolutionary Guards, a connection that may have proved crucial in his selection by the Assembly of Experts clerical body.
One of the few official insights into the importance of Mojtaba Khamenei came in November 2019 when the US Treasury announced sanctions against him and other senior Iranian officials, including Golpayegani, on the grounds they were pushing Iran's "radical" agenda around the world.
The US said he was designated for representing Ali Khamenei "in an official capacity despite never being elected or appointed to a government position aside from work in the office of his father".
"The Supreme Leader has delegated a part of his leadership responsibilities to Mojtaba Khamenei," the US said, adding that he had "worked closely" with the commanders of the Quds Force -- the Guards branch responsible for operations outside Iran -- and the Basij militia "to advance his father's destabilizing regional ambitions and oppressive domestic objectives".
A sign of his potential sway came during the 2005 presidential elections when former parliament speaker Mehdi Karroubi wrote a letter to the supreme leader complaining that Mojtaba Khamenei had been intervening on behalf of his ultra-conservative rival Mahmoud Ahmadinejad.
Ahmadinejad went on to cause a sensation by defeating former president Hashemi Rafsanjani. Mojtaba was again seen by some commentators as coordinating the crackdown on protests that followed Ahmadinejad's disputed 2009 election victory.
A leaked US diplomatic cable from 2008 published by Wikileaks said that Mojtaba was "seen by many second only to Golpayegani within the office of the supreme leader".
- 'Unlikely' to have father's influence -
According to an investigation by Bloomberg, which cited anonymous sources and Western intelligence agency reports, Mojtaba Khamenei has amassed wealth estimated at more than $100 million.
It reported he has earned money from oil sales channeled into investments in luxury British real estate, hotels in Europe and property through shell companies in tax havens.
Born in his father's home city of Mashhad in northeastern Iran, Mojtaba Khamenei studied theology in the clerical hub of Qom where he also taught.
"The role of Mojtaba Khamenei is unclear," said Thomas Juneau, professor at the University of Ottawa.
"It is very unlikely at this point that he has the degree of influence that his father used to have."
