Former UN Secretary-General Ban Ki-moon's return home Thursday has brought him closer to his much anticipated bid for South Korean presidency, signaling a tough few months ahead for other presidential aspirants.
It also means a whole new political ordeal for the 72-year-old former diplomat, who now enters domestic politics for the first time as a rookie in the electoral game.
Ban's greatest strength is undoubtedly the public's recognition of his prestigious career as the first-ever South Korean national not only to take UN's top post, but to have served in it for two consecutive terms.
Also, his overseas position has largely kept him away from the political commotion here, particularly the extensive corruption scandal involving President Park Geun-hye, which might result in a premature end to the incumbent administration.
But the longtime absence from his home country is also a weakness for Ban who, unlike his potential rivals, has had little time to gear up for the presidential election, which is likely to take place earlier than scheduled, possibly in around April.
Who is Ban Ki-moon?
Born in 1944, in Eumseong-gun in North Chungcheong Province, Ban began his career as a diplomat by passing the nation's Foreign Service Examination in 1970.
He swiftly built up his career in the Foreign Ministry and consecutively filled key posts such as director of American affairs and chief of foreign policy.
But he faced challenges in 2001, when he was pushed to step down from a vice ministerial post, taking responsibility for aggravated Korea-US bilateral ties.
Ban then took the post of protocol secretary for Han Seung-soo, then chairman of the UN general meeting -- a transfer deemed a demotion for a former vice minister.
It was the former liberal President Roh Moo-hyun who brought Ban back to domestic affairs by appointing him as presidential assistant for foreign affairs in 2003.
Though he was at times criticised for his allegedly excessive pro-US stance, Ban soon gained credit in the Roh administration for his negotiating skills, which he had the chance of proving over a number of diplomatic agendas.
Of them was the six-party talks which kicked off in 2003 to address North Korea's nuclear armament issue.
Backed by the Roh government's full-fledged support, Ban was named the 33rd secretary-general of the United Nations in 2006, becoming the first Korean to take the post.
His elite career, along with his biography titled "Study Like a Fool, Dream Like a Prodigy," has inspired South Korean youths over the years.
Rising to the presidential race
Though his history largely associates him with the Roh government, Ban is known for his amicable ties with all South Korean presidents, regardless of their respective political tendencies.
He is also noted as a rare high-profile civic servant who has served four separate administrations, from the military dictatorship of the Chun Doo-hwan government to the progressive Roh administration.
It was such apparent neutrality, as well as his publicity, which made Ban an appealing presidential successor for President Park and her ruling conservative Saenuri Party.
The plausibility of this happening expanded further, as most of the pro-Park figures lost their political momentum upon the party's crushing defeat in the parliamentary election last year.
Amid speculations on Ban's likely bid for South Korea's presidency, the UN chief official met with Park during her visit to the UN headquarters in 2015.
His favourable remarks over the Saemaeul Movement -- one of Park's flagship projects to develop rural areas -- and his close-door meetings with the president further boosted the rumours of his political aspirations after returning home.
But with the president currently facing impeachment and the Saenuri camp divided in factional feuds, it is yet uncertain whether the diplomat will create a new political entity or join hands with existing groups.
What seems to be certain is that the former UN official is determined to take on a political career upon returning home.
"I am ready to give my all, if only my experience and insight from my 10 years in the UN may contribute to South Korea's development," Ban told Korean media correspondents late last year, just before his tenure was to end.
Also, a group of his aides recently started a headquarters in Seoul and held a press conference there, boosting expectations of Ban's imminent announcement on his presidential bid.
Integrity tests lying ahead
Despite the uncertainties and challenges, Ban nevertheless remains one of the top two front-runners to contend in the upcoming presidential election.
For this reason, a number of political groups have increasingly been seeking to recruit him to their camp or at least to form solidarity in the election.
Standing first in line is the Barun Party, which split away from Saenuri amid efforts to draw a line between the feud-ridden President Park and her loyalists.
But a critical roadblock for Ban is the dispute concerning his integrity, as he is to face a public who is utterly disappointed and infuriated over the president's corruption scandal.
A survey conducted by local pollster Realmeter in the second week of January showed Ban to have 20.3 per cent in approval rating, down 1.2 percentage points from the previous week.
Moon Jae-in, former chairman and top presidential candidate of the main opposition Democratic Party of Korea, took the lead with 27.9 per cent.
Ban's slight downtrend is attributable to the allegations, raised by a Seoul-based weekly magazine, Sisa Journal, that he received bribes worth $230,000 between 2005 and 2007.
This scandal, combined with his brother and nephew's indictment in New York -- also over bribery charges -- seems to have dampened the public's enthusiasm over the returning diplomat.
Another controversy for Ban is the UN resolution, which recommends retired secretary-generals to refrain from government posts in their home state for a while.
Though the clause is considered non-binding, its underlying intention was enough to bring criticism on Ban for stepping into the presidential race immediately after his UN tenure.
A number of opposition figures, such as Seongnam Mayor Lee Jae-myung and South Chungcheong Gov.
An Hee-jung, have raised their voices to condemn what they see as Ban's premature presidential ambition.