Tracer is a character in Watch Pioneer, and Lena Oxton (code name: "Tracer") is the youngest member of the prototype flight test plan of Watch Pioneer. Because of her bold flying skills, she was chosen as the test pilot of the prototype fighter and Jumper that can be transmitted. However, in the first test flight, the launch array of the prototype failed and the pilot disappeared completely. Lena is therefore considered dead. It's a woman.