War of the Century

Endelaus War
Clockwise from top left: Kalythian aircraft carrier KOF Immortal departing for the Endelaus Sea, 1950 - Sarlaiyan EM/VIII fighters over southern Kalythia, 1916 - Sarlaiyan vehicle convoy en route to participate in the Battle of Idas Pass, 1946 - Sarlaiyan foot soldiers regrouping in a trench at the Battle of Dominus Sein, 1923 - Forest fires engulfing the Cardana National Forest during Operation Iron Dusk, 1909 - Ruined streets of Hanna after a Kalythian firebombing raid, 1944
Date 11 March 1905 - 25 November 1958 (53 years, 8 months, and 14 days) Location Kalythia - Sarlaiya - Endelaus Sea Result See Aftermath
Belligerents
Kalythia	Sarlaiya	Coalition of the United Front
Commanders and leaders
Upper Council	Empress Serena XII	JECCOM
Casualties and losses
Civilian dead: 43,000,000 - 48,000,000 Military dead: 17,000,000 - 25,000,000 Total dead: Over 60,000,000 (1905-1958)	Civilian dead: 10,000,000 - 15,000,000 Military dead: 26,000,000 - 37,000,000 Total dead: Over 35,000,000 (1905-1948)	Military dead: 9,000,000 - 15,000,000 (1931-1958)

The Endelaus War, sometimes referred to as the Third Phase of the Azure War (11 March 1905 - 25 November 1958) was a conflict fought between the Empire of Sarlaiya, Order of the Kalythian Star and a large assortment of coalition powers, following the earlier Azure War which took place strictly between Kalythia and Sarlaiya. The latter included support from a multitude of vassal and client states. The war, which directly developed from disputes regarding the sovereignty over several archipelagos in the Endelaus Sea, intensified into a major global conflict after both nations ordered numerous illegal attacks against civilian merchant vessels of neutral nations suspected of aiding the other side.

Kalythia-Sarlaiya relations had remained poor since the beginning of the 20th century as a direct result of ideological disagreements between the generally republican Kalythians and monarchist Sarlaiyans. Both countries had vied for uncontested control of the Endelaus Sea since the early 1890s along with the body's natural resources, especially crude oil and coal. Concerned about Kalythian naval superiority in the region, Sarlaiya initiated the conflict by preemptively sailing a naval task group over the Endelaus Sea and attacking numerous Kalythian coastal military installations, before launching an amphibious assault on the Kalythian southern coast.

The Azure War is sometimes grouped together with the larger Endelaus War by historians and the overall conflict is subdivided into three major phases. The first phase (1905 - 1917) is characterized by the initial Sarlaiyan land invasion along with the various naval skirmishes that occurred in the Endelaus Sea at the same time. The second phase (1918 - 1930) saw a stalemate develop on land as large Kalythian naval incursions interdicted Sarlaiyan maritime supply lines and the naval conflict intensify as both sides committed large war fleets to the region. The third phase (1931-1958) is what is often defined as the Endelaus War specifically, when an international military coalition intervened in response to provocations by both original belligerents.

The Endelaus War was one of the deadliest conflicts in human history, resulting in anywhere between 95 to 115 million fatalities, about half of which were civilians. Allegations of crimes against humanity and war crimes were made against both sides during the conflict primarily pertaining to massacres, use of torture, ethnic cleansing, cultural genocide, employment of chemical weapons, and widespread maltreatment of prisoners-of-war. Following the Kalythian victory, the Empire of Sarlaiya was demilitarized and briefly occupied and tribunals were conducted against suspected war criminals from all sides, overseen by the coalition.

Initial Sarlaiyan territorial gains during the opening years of the war, both on the disputed islands of the Endelaus Sea and on Kalythian home soil, were eventually checked by Kalythian defensive action and more importantly by the Kalythian navy's attacks on the Sarlaiyan supply ships ferrying soldiers and materiel to the front. This compelled the Sarlaiyans to build up more naval strength in the Endelaus Sea and resulted in the focus of the war shifting from the land invasion to the proliferating naval actions at sea. This period saw both sides utilize new advancements in naval technology including dreadnought battleships, early forms of naval aviation, sonar, and submarines. The campaign culminated in a series of large fleet engagements which inflicted widespread destruction on and crippled the navies of both sides. Attacks on merchant vessels of neutral nations by either side, both intentional and unintentional, drew a number of countries to create the Coalition of the United Front to fight against both Sarlaiya and Kalythia. Unable to disrupt Sarlaiyan supply lines and facing more amphibious invasions further west by the coalition, Kalythian defensive efforts began to falter on all fronts. Sarlaiya suffered similar invasions on its own soil by the coalition and despite renewed success against Kalythia, fought an even more debilitating campaign against the coalition that ended in the Sarlaiyan surrender in 1948 and its withdrawal from the conflict. Further fighting continued between the Kalythia and the coalition until the official conclusion of the war in 1958 after a total of over 53 years since the outbreak of hostilities.