Well, the best thing you can do is to try and win as many battles without losses.
Another thing you can do:
Start a new game. Do the main quest line till you get the spirits of rage box. Doing the missing skull quest in the castle in Velarion forest is also advisable. Then scout the adjacent areas for leadership flags, chests, etc. With this at hand, the starting fights will be much easier.
And of course, learn to kite the archmagi away from the camp. having a strong tanking unit is a blessing.
|