Enough with This Slow Life! I Was Reincarnated as a High Elf and Now I'm Bored: Volume 8

Shortly after Soleil reaches adulthood, she sets out on her own path in life, a road neither Acer nor Airena would have ever anticipated. But they don’t have much time to stew on it, as shortly after her departure, they find themselves leaving Pantarheios as well, heading out to begin reconstruction efforts on the southern continent. After over a hundred years in the south, Acer returns to the north to find it has changed considerably in his absence. The nation of Ludoria is no more, the Yosogi family has become a nation of its own, and the former states of the Azueda Alliance have separated, waged war, and unified again under the name of Azuetta. As always, the world continues to change around him.

[From J-Novel Club]