She did speak in riddles...which means that it might not be an armada of sorts, but a single being, or possibly one that does not know they are but is destined to become. So maybe it could Revan or the Exile who become the True Sith.
Kreia said the True Sith was in the unknown and Revan went there to stop it and did it without any allies or attachments. Maybe he foresaw himself becoming the destruction of the galaxy and left everything to save the galaxy from him.Or maybe it was the Exile he foresaw and went to find the Exile in the Unknown thinking S/He was there and now waits for His/Her arrival.
Yesterday is history. Tomorrow, a mystery. Today is a gift...that is why it is called the present.