To act as a flagship for.
The most important one out of a related group.
The ship occupied by the fleet's commander (usually an admiral); it denotes this by flying his flag.
The ship regarded as most important out of a group, e.g. a nation's navy or company's fleet.
To act in the role of mastermind.
A person responsible for the highest level of planning and execution of a major operation.
A person with an extraordinary intellect or skill that is markedly superior to his or her peers.