The Mountain Lemur Royal Family were a family of mountain lemurs from the Mountain Lemur Kingdom. The earliest known member (although it is implied the family went back further), is the unnamed Mountain Lemur King, the father of Koto and Sage. In the kingdom’s known history, the throne passed from this unnamed king to Sage, though he did not want to be king and instead passed the throne to Koto, his younger brother. The only remaining (known) living member of this bloodline is Sage, after Koto died in an accident at the end of the War of the Beasts. Sage then assumed the throne from his junior brother, and eventually married Clover, therefore continuing (and diversifying) the royal bloodline.
Koto and Sage’s father and mother were the first rulers of the Mountain Lemur Kingdom mentioned on the show. Very little is known about them other than their existence. It is known, however, that they had two sons, the oldest of whom would become their successor. The king attempted to pass the throne to Sage, but he refused the crown and left the kingdom to wander. Koto assumed the throne instead. At an unknown time, they passed away.
Koto succeeded his father after his older brother passed down the opportunity to be king. Koto was known for ruling violently, using all expenses on building up and training his military, so much so that the kingdom had little to spend in food or education. They were left with “no choice” to attack other kingdoms on the island. Koto rules for a while alone, though he did nearly marry Princess Amy in an attempt to form an alliance with the Crocodile Kingdom. Eventually he died in an accident caused by King Julien of the Lemur Kingdom.
While he previously tried to avoid being king, Sage had to assume the throne after his brother died because there was no other (known) living member of the bloodline. He moved the kingdom back to its original location, and set up a new functioning kingdom. Towards the end of the show, Sage married Clover.
At the end of All Hail King Julien, Clover takes Sage as her husband and moves to the Mountain Lemur Kingdom with him to become queen. She is popular amongst the mountain lemurs, who take a liking to her warrior-like attributes and skills. She is presumably one of the first non-mountain lemurs to marry into the royal mountain lemur family.