The Vanishing Oracle

In the small town, Portus Lemanis lives a renowned oracle by the name of Cassandra Lemanis, she is the leader of the temple in the town. The town itself is nothing special, a typical Dercian port town where a few merchants come each week for trade and exchange rumours of where to best conduct one's trade. beyond the town, the area is littered with stones said to be the remains of an old wall around the town that never got rebuilt.
Not much is known about Cassandra but from an early age, it was discovered that she possessed the ability to fade from the mortal plane into another plane where she is able to get glimpses of the future. This ability has meant that seekers from all over the Empire of Dercia come to Portus Lemanis to seek the guidance of the oracle. 
The glimpses of the future that she is able to see are not always what is guaranteed to happen, countless things have an influence on the future, these things can be anything from forgetting to tie one's sandals making one late for a meeting to saying one extra prayer to ones chosen deity in the morning resulting in the deity nodding one towards a slightly better future, Due to these and countless other reasons, the glimpses Cassandra can see might not become real but her sightings have a higher rate of becoming true.
Lately, she has reported that something lurks in the future, something dark and dangerous, something that will bring devastation to many parts of the Empire and possibly even beyound the borders. This prophecy has resulted in the Palace in Pearlhal sending scholars with the task of trying to decipher the meaning of this darkness.