Known famously throughout the world as humanity's strongest contractor. Whatever legal or illegal, if paid she will get it done. A master of disguising, sound imitating, lock picking (even ones with fingerprint scanners), and mind reading.

In the first book, Jun was invited to help solve the murder on the island, but she does not appear until the novel's epilogue and sheds new light on the murder case. At the beginning of the book, Ii-chan presumes that Aikawa is a man.

She shares a friendly relationship with I, but he is often troubled by her presence.