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The Alchemist also has multiple functions: Firstly, you can upgrade your health potions in exchange for crafting materials and gold.

Elixirs and Incense

You can also craft Elixirs and Incense. Both can be used to increase some stats for 20-30 minutes, with the difference being that Elixirs only apply to the user while Incenses apply to all nearby players.

Alchemist Crafting

The alchemist can also craft (presumably rarer and/or higher level) crafting materials from other materials and some gold.