Byakkou

Shironiji is a Summoner and she participates in Operation Capture as a member of the Watermaple Consulate Raid Party.

Fallen Guardian arc
She appears in the Watermaple Consulate Raid Party training grouds, bringing Seine with her, and she asks if they could participate.

She tags along Mikakage in Team F, where she summons a Golem to protect Akatsuki and lates she  hits Nelles with  as Akatsuki and Maryelle head to the next zone.