5:50 You were thinking of Alexei Navalny, and yeah, the Ukrainians didn't like him that much. He did not oppose the annexation of Crimea (he changed this position later) and, like most of the Russian opposition, didn't really do much. Yevgeny Prigozhin is probably much closer, he had command of the Wagner Group and did rebel against Putin. However, he did not die in prison but was blown up while on his private plane.
5:50 You were thinking of Alexei Navalny, and yeah, the Ukrainians didn't like him that much. He did not oppose the annexation of Crimea (he changed this position later) and, like most of the Russian opposition, didn't really do much.
Yevgeny Prigozhin is probably much closer, he had command of the Wagner Group and did rebel against Putin. However, he did not die in prison but was blown up while on his private plane.