Aoi in Assassin's Creed Shadows is a contact you get from Lady Nene when pursuing the The Naginata Shinbakufu, and you need to find her as part of the 'An Evening in Otsu' main story quest.

In this Assassin’s Creed Shadows guide, we’ll walk you through how to find Aoi and how to find the lead on Seta Bridge. Note that you won’t be able to start “An Evening in Otsu” until ...