The Scribe of the Demon King's Castle

Fatalia is a transmigrator, a young white-haired succubus, a pitiful child who somehow ended up in the Great Wilderness, burdened with a useless system in her mind that only displays interface data. But one day, she successfully discovered another use for this useless system. Faced with an abyss where rewards come at a price, she declared, "I will sacrifice the system." And she succeeded. (This is a serious story of a succubus assisting a demon king in his plan to overthrow the world.) (Just to emphasize, it's an orange-themed story because the tag is gone.) (And just a heads-up, the protagonist grows up; her mature appearance can be seen on the cover, she's not always a loli.)