Fall of Zelensky's top aide - reboot for Kyiv or costly shake-up?

Andriy Yermak was a constant, looming presence in Ukraine's government - a seemingly immovable figure on the political stage.

Despite his towering frame, you might not always have spotted him. Yet, wherever President Volodymyr Zelensky was, Yermak was often not far away.

As his chief of staff, Yermak wielded enormous power at the top of government and was even trusted to negotiate on Ukraine's behalf at peace talks with the US.

But as his influence grew, so did public resentment of the power this unelected official held. His political career came to an abrupt end on Friday, hours after anti-corruption investigators raided his home in Kyiv.

Yermak and Zelensky first met in 2011 when the former was an intellectual property lawyer and the latter a TV producer.

After working together during the successful presidential campaign of 2019, Yermak became Zelensky's chief of staff. He stood next to the president as he gave his now famous "we are still here" speech as the Russians descended on Kyiv at the start of their full-scale invasion in February 2022.

As Zelensky concentrated his power over time, Yermak was widely viewed as the second most powerful person in Ukraine. He reportedly helped shape foreign policy, ousted political rivals and even made battlefield decisions.

Ukrainian politics is shaped by big characters, and Zelensky's administration had not one, but two of them.

Despite the favourable conditions Yermak enjoyed within the sprawling Presidential Office, the same couldn't be said outside its steep walls.

His popularity was nosediving.

Zelensky had successfully grappled with corruption scandals in the past, but in July a chain of events began that has shaken the current government to its core, weakening him politically and costing him his right-hand man.

That month, the president convinced parliament to formally remove the independence of Ukraine's two anti-corruption bodies and bring them under direct government control.

At the time, Zelensky said it was to limit Russian interference.

But the public - as well as the European Union - disagreed, and he was forced to U-turn after mass demonstrations.

At a time when Ukraine is fighting and negotiating for its very survival, his resignation is hugely destabilising.

Talks will continue next week. Ukraine's presidential office said on Saturday that Defence Minister Rustem Umerov was the head of a delegation heading to the US.

What is not known is whether this will be a timely reboot for Kyiv, or a costly lack of continuity.

It is also not known how Yermak is taking his sudden departure from government. The New York Post reported on Saturday that he had texted their paper and vowed to go to the front line. He also declared his innocence.

"I'm going to the front and am prepared for any reprisals," he reportedly said. "I am an honest and decent person."

But there is a feeling that Yermak's departure is a sign of positive change.

"Let's call it what it is: good news," says Olga Rudenko, editor of the Kyiv Independent.

"Think about it: a young democracy like Ukraine has independent institutions that are strong enough to investigate the most powerful man in the country - and to do so during the war.

"People rooting for Ukraine around the world aren't rooting for a place on the map, but for a place living by certain values - and fighting for them. Today we see these values in action.

"This shows why Ukraine is exactly the country worth supporting."

Additional reporting by Toby Luckhurst