Guardian Questline in Mathosia
Starting in the Tutorial zone of Mathosia, then moving onto the Guardian controlled zones of Silverwood and Gloamwood and onward to the rest of the world.
Mathosia (the continent) will provide you with quests to level up to level 50.
Ember Isle is a level 50 zone, but it’s built to be challenging so you will likely find it easier to go straight to Storm Legion areas and come back to Ember Isle at a later date.
Planetouched Wilds is also in Mathosia, this is a level 65 zone so you will come back to quest there after completing Storm Legion and Nightmare Tide areas.