Are you referring to the ghost in one of the central two cells on the prison level, on the west side?
Part a post I made in the
Killing Fergus topic, who you should reach shortly;
How have you distributed your stat points? If you increase your Survival and Speed, it helps a lot. For both characters, at level 2 I bumped Strength up to 6, left Intelligence at 1, and got the rest to 3. ... My first time through the demo I put more into Strength and Agility right away, and had more difficulty with Fergus. Doing better damage doesn't always compensate for being slower or attacking second.
If you have one character use a bow (from the middle cell on the west side) or magic (later in the game when you have more powerful spells), the other character can either run around distracting an opponent or using hit and run tactics, while the first does most of the damage from a distance.
There is food and water in the north west cell, which you can use to sleep in the haystack in your original cell, to replenish your health and mana. That may help you conserve potions.
Have you explored all of the other cells?
