"The Legend". Problems with the walkthrough.

You have different tactics and troops for different opponents – but where will you get them (or carry them in reserve), or constantly fly around to different islands to get them? I still have all my dwarven troops, even though I've almost cleared the elven lands. There's nowhere to replenish them, only to exchange them for local ones...

I exchanged troops for local ones as soon as I arrived at the elves. Two stacks of dryads allow you to clear almost all elven lands without losses. Two pockets are always enough to change tactics. Either put archers in a pocket, then bring out melee troops, or put melee troops in a pocket, divide the dryads into two stacks, and the archers and fairies take out the sleepy enemies. It's boring, but very effective. And the Ruby of Angi shows what it's capable of. There's also a strong combination – a fairy gambit, time warp on the fairies + mirror of pain. I specifically selected troops only for the battle with Karador. But I didn't return to other islands. If I came across ancient ents, I always took them; they are the most resistant to undead attacks.