It's Game of Thrones at Viacom: Dauman vs. his mentor Sumner Redstone

Media mogul Sumner Redstone for years has lavished praise on his protégé, Philippe Dauman, calling him “the wisest man I have ever known,” and trusting him with the keys to his corporate kingdom.

Not anymore. The ailing mogul abruptly removed Dauman from his family trust last week, suggesting that...