Tsukasa Hiiragi

Tsukasa Hiiragi (柊 つかさ, Hiiragi Tsukasa) is one of the four main characters of Lucky Star. She calls Konata Izumi "Kona-chan" and is the only one among all the Lucky Star characters who does that. She is the younger twin sister of Kagami Hiiragi, and is also a member of the Hiiragi family.