Maki

"Spiral Shell" Maki is an assassin working for the Seto Group, as well a devoted friend of Sun. She, like Gōzaburō Seto, dislikes the idea of "losing" Sun to Nagasumi, and will often distract Sun with sweet talk in order to fire her shell gun at Nagasumi. She also thinks that Nagasumi and Luna should be together.

(Source: Wikipedia)