(Bloomberg) -- Epic Games Inc. Chief Executive Officer Tim Sweeney sought moral high ground on the first day of a trial against Apple Inc., saying he sued the world’s most valuable company not to boost sales of his Fortnite game but to stand up for developers cheated out of commissions by the App Store.

Apple claims in court filings that Epic set up a public relations campaign last year to make Apple look like a “bad guy” to “revive flagging interest in Fortnite.”

Sweeney, the first witness to take the stand in federal court in Oakland, California, said the lawsuit accusing the App Store of behaving like a monopoly while taking as much as a 30% cut from developers had nothing to do with Fortnite usage. “The lawsuit is entirely about Apple’s practices,” Sweeney said when questioned by Epic’s attorney.

Sweeney said he waited to sue Apple until last year because it took him time to realize the “negative impact” of App Store policies. “It got to the point when Apple was making more profit from a developer’s app in the App Store than the developer was making himself.”

Epic’s 2020 revenue totaled $5.1 billion, Sweeney said. When asked by Epic’s attorney how important Apple’s iOS is to his company, he said it was “vital.”

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