Marshmallow Justice (二言目) is the second opening theme of the Nisemonogatari anime. Performed by Eri Kitamura, who voices Karen Araragi, it is featured in Episode 2, and from Episode 4 to Episode 7.
Lyrics
Japanese Rōmaji
English Translation
Video
http://veehd.com/video/4708131_Nisemonogatari-ep-02-OP-1920x1080