Nilkawt rarely has a prime minister but frequently has a sub-prime minister. The sub-prime minister usually also holds the position of Great Saviour of the Treasury and is usually known by that title.
Most of the irrelevant, usual functions of a prime minister are quite easily handled by the Government of Nilkawt's public relations department, which is mainly staffed by graduates of Nilkawt's National School of Acting and Effective Action.
There is nothing else to be said about the duties of a prime minister or sub-prime minister, really. Please note that the Great Saviour of the Treasury is usually referred to as the GST.