Chigusa is an onmyōdō charm user working for the Kansai Magic Association. She's best known for the chaos she stirred up during the school's Kansai field trip—and for her role as the antagonist of that arc.
Her main motivation stems from a deeply personal grudge. Both her parents were killed in a major magical war between Eastern and Western mages roughly two decades prior, and she never got over it. Rather than move on, she nursed plans for revenge against the Western mages, and those plans centered on Konoka, a girl whose magical potential caught her attention immediately.
Chigusa's scheme was ambitious: she wanted to summon Ryōmen Sukuna-no-Kami, a demon god, which required access to Konoka's enormous magical reserves. She actively worked to keep Negi from delivering a letter to the Kansai Magic Association's chief, figuring better relations between the Kansai and Kantō branches would only complicate things. Beyond her own abilities—she could summon warrior spirits and create shikigami—she brought in three mercenaries to bolster her operation and help secure Konoka.
The plan actually worked at first; she successfully summoned the demon using Konoka's magic. But Evangeline stepped in and dispatched it without much trouble, which meant the whole scheme fell apart. Chigusa tried to flee the scene but was caught by Chachazero and handed over to the Kansai Magic Association's custody.
She's physically distinctive, often noted for her notably large chest.
Content compiled by AnimeList.moe from publicly available sources.