There is a technique I used for defeating the whole first island no loss - but only on hard diff. last night
Unfortunately have to leave town for business for few days, but if it helps anyone on impossible. diff. then that's great.
idea: use Skald, learn order magic, learn Edda, the rest is your choice. With a bit of luck you'll find 2-3 nature call scrolls and 2 x mana boosting shrines. Ideally 3 scrolls + 2 x mana boosting shrines + mana boosting items (+5 gloves..)
Upon starting a fight,cast song of Helheim then cast nature call using mana. Since it costs 20mana, you'll be left with 10-15mana. Song of Helheim recovers mana - nicely positioned ice storm attack by soothsayers recovers 5mana. Bit of skirmish enables to cast nature call again in second round. Note : Mana 30++ to start with is not strictly necessary. you should be able to get your second Nature call casting during second round somehow. Advantage however is to be able to cast it at the very beginning of round 2 - give enemy units & hero more targets. In third round I did not manage to get 20mana out of it, however if desperate, you can use a stock scroll of nature call. This way, if you had 3 x starting nature call scrolls, you can : - 3 x nature call casting against Ahriman
- 3 x nature call casting against lvl10 Necro below
- 2 x nature call casting against Eric and any other tough stack
Hope it helps.
Someone asked earlier if wanderer scrolls can be found on the first island. I found Gift of stones in the chest during battle. It raises runes of troops to 3..