When Mufasa and the children were still running around the hunting grounds, the other Players led by Marni had already arrived at the Seira Marshes.
Occupying a major chunk of the Valla Empire's territories, the Seira Marshes were uninhabited like the Trinia Forest up north, being an inhospitable place for humans that was overflowing with beasts and magical beasts. In fact, whenever Valla's Emperor bore ill will towards any noble, the most common solution was to award them a piece of land out of those two regions while urging them to hurry towards their fief with all pomp and ceremony…
Of course, such a solution was just useless to important nobles like Duke Horan who already owned vast tracts of land.