Head of Government
The Head of Government is the Leader of the Executive Branch of a Nation, who is no lower than second-in-command of a nation (i.e. they answer to max 1 person). They can simultaneously be the Head of State, or not, depending on Government Structure.
Former Nations
EotLP
Although the Emperor of the Lego Plains was technically the Head of Government, due to the EotLP's unique situation as a directly ruled Monarchy, many people argued that the General of the Imperial Armed Forces of the EotLP held a role closer to that of a Head of Government, both in terms of their position as the chief delegate of the Emperor, but also for the power which they wielded over the nation, considering the deep level of connection between the EotLP Military and every level of society, as well as Emperors Sergio Ren & James Krennic's consistent use of the Military as the primary operative branch of the Government.
General Tiberius Rex - who was General from the 33rd of Mara, 247, until the dissolution of the EotLP on the 38th of Actaber, 271 (totalling over 24 years) - had a deep level of control over the Nation for large parts of his tenure as General, initially caused by Emperor James Krennic's decline in Health & Mental Aptitude (generally considered to have started around 252). As Krennic's health & mental ability disabled, Rex became the de-facto leader of the nation, and was unofficially recognized as such by other Nations. He ceased to have a day-to-day Military Role such as would be expected of a General, and spent much more time governing.
Following Krennic's Death (without an apparent heir) during the Third Balkavanian War, Rex was left in effective control over the Nation. As he had already placed the nation under Military rule (Which had no constitutional basis, but was allowed because of the power he wielded and the general lack of legal framework for governance in the EotLP) in 259 following the outbreak of the war, He decided not to attempt to replace the Emperor until the conclusion of the War. This illustrated the power of the General even more clearly than before, as he maintained effectively the same control over the nation as he had under Krennic's reign, and also had granted himself the status of Emperor-Maker, by choosing not to decide who the next emperor should be.
As he was aging, Had recently lost his spouse, and was a Leader in the Largest War in Balkavanian History, Rex did not intend to continue running the Nation after the conclusion of the war, and hoped that Ren's original vision of a peaceful transition to a Democracy may yet be realised. In order to achieve that, He announced that Krennic's Successor would be Duke Mikael Cagne, who had deep roots in Cagne Island, and who had previously discussed openness to Democracy. Cagne turned out to be a disappointing choice, and he took a large portion of the Military's Governance Power away from it in his first years in office, a move which the intending-to-retire Rex approved of. Cagne didn't intend to yield to the people, despite his earlier comments, and instead intended to weaken the power of his only political rival in order to solidify his base of power as Emperor.
When finally Rex realised that there was no chance of Cagne choosing to grant democracy, and that the people of the EotLP had a huge wish for a transition to a democratic government, Rex announced, as the General of the EotLP, that the Military wished to see a Transition of Power to the people. Cagne refused, and in the short power struggle that followed, Rex was arrested by Cagne's Imperial Guards, but was then freed by Military Units operating under the orders of Marshall Anthony Fovren, before Cagne was arrested. Rex then officially became both the Head of State & Government of the EotLP, as not only the Emperor Emeritus, & General of the EotLP, but also through the official position of Chairman of the Board of Democratic Transition.
Throughout his Tenure as General of the EotLP, he was effectively the Head of Government of the EotLP for over 11 years.