Sula is an "apprentice female mercenary" at the Scarlet Flame Mercenary Fortress. At the age of 20, she received a test given by the captain of the Scarlet Flame Mercenaries. If she could pass this test, she would be promoted to a "regular mercenary," which had always been Sula's heart's desire! The captain gave Sula the test of spending a night in the suburbs where a pack of wild wolves gathered, and she was not allowed to leave.