So it is little wonder that the Persians found the cat an invaluable ally even at the height of battle.

Although a fully trained field agent, Taylor's specialty is human medical research, making her an invaluable ally in the fight against chemical and biological weapons.

Captain Birch had proved to be an invaluable and unexpected ally.

On other occasions, these villains return reformed, becoming invaluable allies or gaining a larger role in the story.

"They were an invaluable ally and fought shoulder to shoulder with us at a time when we needed them the most."

Both became invaluable allies to the end.

By secretly giving inside information to the Komnenoi, Maria was an invaluable ally.

What had made him an invaluable ally now made him the deadliest enemy.

It is an invaluable ally for the European Union.

Her powers make her an invaluable ally against the many foes that they encounter.