On Monday, Stephen Mwiti, 48, who said he had lost all six of his children to the cult, welcomed the verdict.
“I’m a happy man, that all persons have been convicted,” he told the BBC outside court.
His former wife was one of those convicted of murder alongside Mackenzie.
Delivering her eight-hour judgment in the port city of Mombasa, Justice Diana Mochache said Mackenzie’s followers believed he was “Jesus’s mouthpiece”.
One of his co-accused told the court that Mackenzie had said anyone who resisted fasting must be forced to go to heaven “through kicks and blows”.
Burials in the forest where the cult was based were described as “weddings”, with those who died celebrated as having “wedded with Jesus”, the judge said.
Mackenzie and other cult leaders also face separate cases involving terrorism, radicalisation and denying children an education.
The murder verdict is the first ruling on the most serious charges against the pastor, who was arrested in 2023 after more than 400 bodies were discovered in shallow graves in Shakahola forest, near Kenya’s coast.
He is due to be sentenced on 6 November.
Additional reporting by Thomas Mukhwana