Possum is a false identity/nickname for Anastasia.
Behind the scenesEdit
When all the specific references made in the game are added up Anastasia between 18-28 (though she doesn't look much older than 12). The fact that Caldaur stopped ruling some 40-50 years before the story in 1646, and Anastasia was born in 1668 shortly before her parents death that year, would place KQ2 somewhere between 1686 and 1696. This would make Anastasia 18 on the low end to 28 on the high end. The Llowh'wof's letter would correspond to a longer date, as the letter discussing their infiltration of the swamp was written over twenty years before the story.