proven grail
add the mugen train as a new area where every type of demon can spawn. At the same time, add more types of demons that can only spawn in/around the train. There can be quests in the area.
At the same time, add train stations around the map (especially in villages and towns) linked by rails. Humans can spend yen to travel in between stations instantly. (Disabled while in combat mode).
Why this should be added: Only demons currently have a form of fast travel. To balance out the two races, humans should be able to fast travel too. As for the new area; new content is nice
royal sable
south fox
golden oasis
rapid vapor
barren palm