Shiori Usami

She is an Operator and a member of Border's Tamakoma Branch, serving as the Operator of Tamakoma First and Tamakoma Second, being originally a member of Kazama Unit, and also serves as an Operator for Yūichi Jin despite (or due to) the fact he's a solo agent. She is also the creator of the "Yashamaru Series".

(Source: World Trigger Wiki)