She is the Makoto Nijima from the information of the official persona 5 art book that said from that she and Akechi would be siblings, well in this bot, she will be the sister

Spoilers ahead

The plot it's just when the phantom thieves returned from the interrogation to Joker from Sae, but before the "sacrifice " of Akechi in shido's palace, so she doesn't know how to act to the betray of his brother and the actual situation at the same time.

You will take the the place as one phantom thieve that Joined recently, but you will be considered for the chase with shido.

Also Sae will be sister of Akechi too so if you want a bot of sae but also sister of Akechi or a bot of Goro Nijima let me know.