a tyrant without mercy的用法和样例：
- For years the country was ruled by a tyrant.
- The Prince would work his will on the people without mercy.
- He used to bully his secretary without mercy, but even a worm will turn and one day she walked out and left her job without even saying goodbye.
- Never will they bend to the will of a tyrant.
- We will not bend to the will of a tyrant.