SEOUL • As the natural heir to the family controlling Hanjin Group, Walter Cho was catapulted to the top job at the scandal-plagued South Korean empire within weeks of his father's death. Now comes the hard part.

Mr Cho, 43, assumed the position of chairman last month by virtue of being the only son of the late patriarch, sparking scepticism on whether he is capable of leading the airlines-to-logistics conglomerate founded in 1945.

He may get a chance to prove his doubters wrong later this week when he hosts the global aviation industry's biggest annual conference in Seoul, as president of the group's flagship Korean Air Lines.

Mr Cho's inheritance brings with it challenges, including fending off a siege by activist investors.

But the biggest of them may come from his own family.

There is speculation of an internal feud, with Mr Cho and his two ambitious sisters owning stakes of similar size in the group's holding company. Mr Cho's grip on the empire could become tenuous if the siblings seek to claim a greater role.

"The most urgent task for Walter Cho is to finalise the succession," said Mr Park Ju-gun, president of corporate research firm CEOscore in Seoul. "He has to show his own vision and prove he's different from his father. So far, I haven't found a reason behind his appointment except for the fact that he's the only son."

The speculation over a family rift started this month after Hanjin Kal Corp, the group's holding company, missed a deadline for an annual filing to South Korea's Fair Trade Commission (FTC) on who will head the businesses after the April 7 demise of patriarch Cho Yang-ho.

The FTC, in a statement then, attributed the one-week delay to Hanjin's failure to arrive at a consensus on the next leader.

A representative for Hanjin Kal declined to comment. Calls to Mr Cho's office were not answered.

The family intrigue comes as the conglomerate is seeking to put behind a string of scandals that refuse to fade from the public's memory: One of Mr Cho's sisters hit headlines worldwide a few years ago for the infamous "nut-rage incident" and most recently, his late father was charged with embezzlement.

The scandals triggered a public outcry in South Korea against the privileged and re-ignited debate over whether the country's vaunted chaebol - family-run conglomerates - hold too much power and influence.

Despite the controversies, Mr Cho's sisters played a key role in building the brands of the carriers they oversaw.

"Heather and Emily seem to have the willingness to get back their management rights although they are barred from participation due to the past scandals," said Mr Chung Sun-sup, chief executive officer of business researcher Chaebul.com.

The Cho family and its closest allies own about 29 per cent of Hanjin Kal, with the siblings - Walter, Heather and Emily - holding about 2.3 per cent each.

Should Mr Cho acquire the late chairman's 17.8 per cent stake, that would hand him the biggest holding in the firm, but standing in the way is a 50 per cent inheritance tax, among the highest in the developed world.

Compounding Mr Cho's woes are activist investors who have been targeting the chaebol for their comparatively weak returns and lack of shareholder transparency.

Showcasing their power, shareholders of Korean Air in March voted to remove the then-chairman Cho Yang-ho from the board of the carrier days before his death. The late patriarch was facing trial for allegedly embezzling 19.6 billion won (S$22.7 million) in the five years to 2018.

BLOOMBERG