Description:
The story takes place after an abominable war that foisted a "devil's contract" upon a land. Cecily Campbell, a former noble's daughter who joined a knighthood, encounters a man who dispatches some hoodlums with one sweep of a mysterious sword. The man possesses the power of the same "devil's contract" that has become taboo, now that peace has been restored. Cecily has been searching for a blacksmith who can repair an old sword she inherited from her father, and that mysterious young man happens to be blacksmith named Luke. This encounter launches their adventures together.
Source: Baka-Updates
http://www.mangaupdates.com/series.html?id=41632
Amazed this series was not found in the manga section despite it being mentioned in it's anime section. Anyway, pretty interesting series as there is more material presented than what was seen in the anime.