Lucia

Lucia/Lukia is the older sister of Maria Naruse, and the daughter of Shella.

Lucia seems to share a few traits appearance-wise with her sister and mother, with an exception of shorter hair.

Despite her younger looks, Lucia appears to be a stoic, cool-minded and disciplined woman who focusing on her duty as a maid.

(Source: Shinmai Maou no Testament Wikia)