Royal Knights (Etrand)

The Order of Royal Knights is an order of knighthood in the Kingdom of Etrand, best known for being the personal bodyguards of the kings, best known for their somewhat "eccentric" oath to always be loyal to the living king/queen, even if he/she is legally deposed or abdicates on his/her own. The order was founded under the second reign of King Hereric the Blood-Handed around 110 AEKE, although what was founded at the time would be unrecognisable to today's Etrandish: the order started taking up its current shape in the late 3rd and early 4th centuries, when - presumably under the influence of the Knights of the Blood Red Light, the golden standard of knightly orders even to this day - the order went through a series of reforms and went from simply being elite bodyguards to being actual spellcasting paladins, effectively taking up its current shape that we recognize it in.

The Oath
Royal Knights don't just swear to their very lives to defend the monarch: they swear to serve and be loyal to the least recently crowned living monarch of Etrand. In other words, if King A is deposed or abdicates voluntarily in favour of King B, the order's oaths still oblige them to be loyal to and serve Ex-King A, not King B - that is, until Ex-King A dies, then they are expected to automatically swear fealty to King B.

The king who orchestrated the order's founding, Hereric believed that this was a sure-fire way to prevent - or at least cripple - any attempts to depose him and his descendants, and he was right: even though Etrand would see instability and rebellions every now and then, legally crowned kings would never be deposed again and all attempts to depose them would end up as stillborn failures. And while there were still attempts later to depose legally crowned monarchs - such as the Etrandish Succession War of 718, and earlier the time period between 195 and 222 when the anti-kings Carolus Brynling and Hereric Brynling effectively ruled over half of Etrand as independent warlords - the threat of the best of the best warriors Etrand has to offer breathing down one's neck seemed like a threat sufficiently strong enough to deter potential usurpers.

This might explain why after the 4th century, would-be-usuerpers instead chose to become political manipulators who infiltrated the high circles of the monarchs they wanted to depose, and made them their own puppets instead of all-out deposing them, in order to avoid the wrath of the Royal Knights.