tactics
spell choice
These spells are worth considering:
summon elves
summon centaur
summon eagle
judgement
gorgon stare
safe haven
Immediately after the cutscene move as far north as possible to avoid being attacked.
This is a safe spot that can be used to build up your army.
cross river to first PoP
There are mountains to the east and a river to the west.
To the south is a bridge crossing the river, but it is heavily guarded by chaos forces.
The first PoP is to the SW on the other side of the river.
You can reach it with an eagle or some other flier.
Also by moving along the riverbank you can find a spot where you can cast across the river without going to far south.
A centaur cast across the river can pick up some objects on the far side as well as occupy the PoP.
A little further south is a second PoP that can also be occupied if you are careful to avoid the chaos forces on the bridge.
build an army
It is time to build a pack of centaurs.
With full mana and an army of centaurs it is time to head south.
judgement at the bridge
You will be treated to a cutscene where dwarves are being beseiged by forces of chaos at the bridge (1).
Afterwards you can clear the bridge with little damage to the dwarves or your forces using
judgement.
You could have done this earlier, but afterwards the dwarves head south looking for the chaos mage Pentheus.
Without your army to support them they would have been defeated.
If the dwarves are all killed you cannot enter their mine and will miss that scenario.
chase down Pentheus
Move your army of centaurs south until they find Pentheus and then chase him down.
At some point the dwarves will also enter the chase.
As you lose forces replace them when mana level allows.
You may want to use a judgement to clear out his supporting forces
or better yet a gorgon stare to slow him down so he is easier to kill.
escorting dwarves
Use
elves
and
centaurs
to escort the dwarves.