Trotsky was not a king, prince or royal. He was just a thug.
Apparently you’re hung up on aristocracy as the defining characteristic. And “thug” applies to lots of royals over the centuries, so they’re not exactly mutually exclusive terms. Regarding Trotsky, though, and without introducing any value judgements, he was a political rival for the top job, and when he lost out in the power struggle, he was murdered. Same with your prince.