Village
Alchemist is one of the few free characters in in the game, he unlocks at Level 23, then Papa has a series of quests you need to complete in order to obtain him, once the quest comes to go find him in the forest, he asks you to send some smurfs on the journey, once it's complete, the smurfs come back with Alchemist Smurf. Then you need to upgrade Papa Smurf's hut for 500 
in order to unlock the yellow potion, green potion, orange potion and the magic flask which is unlocked seperatly for 20 
.