Aria the OVA: Arietta

Akari awakens one morning after having an unsettling dream - one where she has fulfilled her goal of becoming a Prima, yet as a result of her succession Alicia is no longer around, and there's an eager apprentice on her hands she has no clue how to handle. Taken aback by the realization that this is what must eventually come to pass, Akari spends her day trying to come to terms with this future reality, and learns a little bit about Alicia's past in the process.