Computer science / game development.
Below are depending on what you actually mean, with suggested paper structures and keywords for each. 1. If you mean the game Territorial.io Suggested paper title: "The Mechanics of Conquest: Game Design and Player Behavior in Territorial.io"
This is an interesting topic, as terratorial.io appears to be a typo or creative spelling of either (a popular .io game) or "Territoriality" (a geographic/sociological concept) combined with the .io domain.
Interdisciplinary (geography, sociology, game studies).