King Henry IX of England, r. 1755-1807
Henry IX "the great" of England, was given the nickname by later historians as the Sun King of the British Isles for his absolutism, involved in several wars on the continent, Asia, and in the Americas which saw Great Britain become the first Supper Power of the world. He'd reform the military in several ways, introducing the Corps system, General Staff, new uniforms, General Conscription, the use of smaller artillery driven by horses, and many others among them.
His first war was the Nine Years War, where he fought alongside what many consider his only peer in Europe, King Frederick the Great of Prussia, inflicting several defeats on France within Hanover personally. The results of the War would see his empire expand into the Caribbean, Louisiana, Argentina, and India, all of which would eventually become pivotal later in his reign, seeing to his rise and various reputations. His later wars would include the War of German unification, where he was able to successfully fight France, Prussia, and Austria over the title of the Holy Roman Emperor, with the support of Bavaria, Saxony, and several other duchies within the HRE. He would create the German Confederation led directly by Hannover, where he'd reward Bavaria and Saxony with lands, Tyrol for Bavaria, and Bohemia and Silesia for Saxony. Thusly, giving both of them the titles of Kings, something both desired greatly, earning their loyalty, whilst he would take the Rhineland for the newly established Kingdom of Hannover. The Egyptian Expedition, where he'd fight with the Ottomans over Egyptian independence, and the establishment of a new Caliphate, ultimately culminating in the Partition of the Ottoman Empire which would see Austria and Russia becoming allies of Britain, overlooking his German conquests. Incorporating Egypt into an alliance that lasts even to this day, securing British dominance in the Eastern Mediterranean, and securing a route to his Indian possessions, which would aid him greatly. The American Revolutionary Wars, where he directed several colonies of Spain to rebel successfully, and then would make them puppets of Britain through several trade and debt traps. The Wars of Indian Subjugation, where he'd incorporate the East India Company into his own possessions and lead, though not personally, to various wars of conquest which would put all of India under him. Finally the French Revolutionary War, which he'd opportunistically use to unite Europe behind himself in a coalition and personally carve up France into several smaller Kingdoms, getting rid of his last rival. Using all of these wars as pretext to take more and more power for himself, until he was able to finally pressure England through fear of the French Revolutionary War into accepting a constitution which gave him absolute authority over all matters of state.
He's seen as a brutal conqueror by both Indians and Amerindians, the man who brought subjugation to their lands, and would abuse their populations for generations, using them to line his own pockets and fuel his conquests further. Whilst also seen as a liberator by the people of Argentina and Egypt, the former for the ability to trade through the Rio De La Plata, the second for his support of independence and the conquests in Cyprus, Arabia, and in on the coast all the up to Antioch. Though the rest of Latin America he was known as the man who'd make them his puppets, using them much like India, which would eventually lead to many wars and entanglements centuries later. Seen as a great conquer by the Germans, leading to his ancestors eventually making the German Confederation into the German Empire, which alongside the HRE saw Hannover dominating central Europe, finishing his legacy. His perception by the people of Britain is mixed, as while he brought them glory, the means he used are seen in a negative light today, whilst he was competent, he had no morals and many scruples, not to mention the countless scandals, though monarchy is seen quite positively today.
The Anglo-American War of Hawai'i.