This it the fourth mission of Myth. Comparing to the previous one it's a piece of cake. You shouldn't (read can't!) have any looses. You are to get the Codex and run away with it. Your units are teleported to the a knot which is occupied by 2 Soulless and 2 Ghols. Kill them (no problem) and had West. Then move towards waypoint 2. You will meet 2 Soulless here so kill them. From waypoint 2 move to waypoint 3. You will face 1 soulless here. Now move along the path. At waypoint 4 you will see wight's body parts. Blow them up so that enemy ghols won't use them. Place your army close to the path and move your dwarves towards the monoment. Secure your archers with few warriors. At waypoint 6 a group of 12 thralls and 3 soulless will attack. Blow them up! Almost at the same time a second wave will approach from waypoint 7 (13 Thralls and 3 Soulless). Take the Codex - it's at the cathedral by waypoint 10 (click your journeyman on it).

As he takes the Codex, he will lead you to the exit. Follow him until you see Ghols at nr 9. Stop and wait for them, they will have explosives. Meanwhile, move your dwarves North so that they can face the third wave (waypoint 11). As you kill everyone you can easily follow the Journeyman to the exit. The more survivors, the bigger chances you will have to win the next mission - Flight from the Covenent. And even with full garnizon, that mission will be very difficult.