Ask Ukrainians who the country's most powerful figure was after the president, and many would say Andriy Yermak, his chief of staff and a key negotiator during four years of war when Western support has kept Kyiv in the fight.
Not any more.
Mr Yermak, a friend of President Volodymyr Zelensky and his trusted right-hand man, resigned today after he became ensnared in an evolving corruption scandal when anti-graft agents searched his property.
The 54-year-old is the highest-profile casualty so far of a corruption investigation that has also seen two ministers step down, and his removal from office leaves Mr Zelensky looking more isolated than at any time since the full-scale war began.
It comes at a perilous time for Kyiv as it faces US pressure to make big concessions to Russia to end its war on his country and lacks enough soldiers or weapons to push Russian forces back.
Concern among US officials over allegations of corruption among senior political and business figures in Ukraine has weakened Mr Zelensky at a time when he most needs their trust.
Oleksandr Merezhko, the chair of Ukraine's Parliamentary Foreign Affairs Committee, welcomed the decision.
"This is the right decision both on the part of Yermak ... and on the part of the president," he said.
"This step ... strengthens the president's position in the eyes of parliament, society and Western partners."
Yermak's long friendship with Zelensky
Mr Yermak, who was born in Kyiv and started out as a lawyer before setting up a media company, had been at Mr Zelensky's side since long before Russia's full-scale invasion in 2022.
They met in the early 2010s, when Mr Zelensky was a rising star in television and Yermak was an emerging figure in Ukrainian media.
When Mr Zelensky ran for the presidency in 2019, Mr Yermak was on his team and later cemented his place at the top of Mr Zelensky's administration.
Whether wearing a sharp suit in the halls of power while visiting European countries or khaki fatigues on visits to frontline positions, Mr Yermak was a constant presence beside Mr Zelensky - a burly figure towering over his diminutive boss.
Mr Yermak had earlier survived several government reshuffles and exudes confidence, despite widespread public mistrust of an unelected official yielding so much power.
He has been a primary point of contact with two US administrations, helps coordinate prisoner exchanges and peace talks, and is involved in lobbying Kyiv's partners for weapons, funding and sanctions against Moscow.
Has the scandal caught up with him?
Little was known about what anti-corruption agents were searching for at Yermak's apartment.
He said he was cooperating fully.
The watchdogs that ordered the searches did not say what they were connected with.
Ukraine has been mired in scandal over an alleged plot to control contracts at the state atomic agency totalling $100 million in kickbacks and laundered money as Ukraine tries to protect energy infrastructure from Russian airstrikes.
Ukrainians are shocked by the scale of the case and outraged that it centres around energy facilities when power, water and heating outages are frequent because of the Russian attacks.
Opposition lawmakers and some members of Mr Zelensky's party had called for Mr Yermak's dismissal, although he has not been named a suspect in the kickback case.
Uncertainty comes at a precarious time
Mr Zelensky remains broadly popular, and sacrificing a close ally could help shore up support at home and abroad at a moment the president himself has described as Ukraine's most difficult.
Mr Yermak's removal could be seen as a commitment to "clean the house" - but also as a sign that corruption allegations are getting closer to the president himself.
The chief suspect in this month's probe is a former business associate of Mr Zelensky's.
In a public address, Mr Zelensky said he had accepted Mr Yermak's resignation in order to try to put the scandal behind him and focus on presenting a united front in the war against Russia and in any peace negotiations.
"I want there to be no rumors or speculation," he said.
Ukraine is under US pressure to accept peace proposals that Russia says must involve Kyiv giving up territory and agreeing to limit the size of its armed forces in future.
Russian President Vladimir Putin has also sought to undermine Mr Zelensky by saying he is not a legitimate leader because he has exceeded his five-year term although Ukrainian martial law forbids wartime elections.
The corruption scandal has also emerged as Ukraine tries to show the European Union it is fighting corruption, a key task for it to join the wealthy bloc.
