Enemy Item Arc

The Enemy Item Arc is the first story arc of Toaru Anbu no Item. Taking place one year prior to the main story, it focuses on the formation of |Item's initial four-person formation and their clash with another group using the name who are running an underground fight club.

Item
In the past, Mugino Shizuri saved Takitsubo Rikou, who had been falsely accused and imprisoned, supposedly done by unscrupulous researchers with the goal of obtaining her as a lab rat. At some point afterwards, Frenda Seivelun joined them as Item's third member under unknown circumstances.

Enemy Item
At some point prior to July, Tokiwadai student Ibotanokikouji Kaede had gathered her own group in the dark side, apparently as a way to distract herself from the oppressive environment of her upper class school and upbringing, which began using the name Item for itself and also ran an underground fight club known as the Colosseum.