The Vertical is about Quest, Plot, and Narrative, while the Horizontal is about Things, Places, and Characters.
Of course Morrowind is inspired by medieval history, the Roman empire, and so on, so it's not surprising that we can look at it from the perspective of 📙 After Virtue, which revolves around how modernity came to be so different from this type of world. MacIntyre talks about the medieval notion of the Quest, and the notion of a Tradition as a community of practice is central to his argument.