This weekend, I started implementing what will go on to become the quest system as well as make up a large part of what endgame will consist of.
A new NPC can be found in town, Elder Uru who, for a price, can sell you portals to dungeons. At the moment, these dungeons are all simply randomly generated caves but ultimately it will be extended to include all kinds of random dungeons. Dungeons contain tougher monsters and of course, better rewards.
The dungeon system will also be used to drive quests. For instance, you'll be asked to venture into the catacombs to retrieve a stolen gem, scour a huge cave to find a kidnapped child or navigate a maze to find and kill a particularly nasty monster.
I'll be working on enhancing the cave system next (adding interesting tiles and items to the area) and also starting work on the actual quest system (including NPCs, a storyline and the engine that will handle conversations).