Blizzard is also working on an elaborate trade-skill system in which players can specialize, for example, in Herbalism, which involves collecting herbs littered throughout the world in order to make magic potions and elixirs (for health, strength, agility, and so on). You'll level up your trade skills by using them, finding trainers, or completing quests--offering a huge optional metagame for those not as interested in bashing monsters. At mid to high levels, players will need to work together for certain trade skills. To create a flaming sword, for example, an alchemist will need to make a potion of flame oil, while a blacksmith will have to forge a particular sword, after which the two can be combined.