Here's one: Sometimes the bros are loyal.
If you are a powerful monarch, you can have a powerful and competent second-in-command, and they won't necessarily try to revolt or usurp you.
- Augustus and Agrippa
- Justinian and Belisarius
- Genghis Khan and Subutai
Augustus, Justinian, and Genghis Khan all had talented underlings with lots of autonomy and they didn't revolt or try to stage a coup.
Now it's extremely dangerous to throw a coup, so it's not just tenderness and gratitude that kept them loyal. But it's good to know that it's not necessarily suicidal to give competent underlings power and autonomy.