Impossible difficulty story so far -
Am at level 7 with the following stats:
4 attack
7 defence
11 int
1750 leadership. No great luck with leadership artifacts (have the same priest rope), infact, no luck with ANY kind of artifacts - I am hoping unlucky now = lucky later
Clearing some last darion quests, and readying myself for the turtle battle.
Had less luck with Feanora's children, I got a
+5% combat experience
+10 to rage
+5 to defence
The 4th baby is going to occupy the ring slot, so I am thinking if I should leave that open for Anya's (?) (the women unit booster) ring. Thank God for no scroll kids!
I have practically only used fireball myself, and also have chaos at lvl 2, with fireball upgraded (650+ damage on primary target). Have 60+ scrolls, from questing, none of which I am inscribing since I don't feel the need to use them just yet! This also means there has been no seller of awesome scrolls for which I need slots available. It also means I can max my alchemy before I start inscribing them en masse later

.
Had much better luck with mind runes; trade is currently at lvl 1, but I am sitting on around 100k already, so I have some doubts about the merit of pumping more in trade.
Some lessons learnt for impossible difficulty. They'll work just as well on lower difficulties too:
- Dodging is practically a necessity. Had given up hope on Feanora since her frog buddies inside Netvill dungeon were guarded by an impossible necromancer and a very hard zombie group. In fact, I dont think I could have actually beaten them unless I was level 15+. The trick that worked for me was to lure the necro really far, and then lure the zombie just enough to pass safely before the necro returned. Don't even ask how I managed the return with that cage.
- Get the horsemen from the knight tent by luring the group guarding it away from it. They are invaluable at impossible difficulty. Combining well with inquistors, you will not lose any of them in battles.
- Sleem is WAY more useful than Zerock (the fire rock) and easier to get! Evil shoals ROCK early game.
- As a mage, you will anyway rely on magic for real damage. For supressing quest artifacts (they are easier to supress than regular artifacts at impossible difficulty), stay around a castle. Move all/most of your regular combat troops out into the castle slots, and fight using free dragonflies, spiders from eggs, cheap snakes from eggs, thorns from sprouts. Your aim is to survive, and you will LOSE troops to the nasty evil gremlins so free troop losses hurt less - They outlive their utility quickly anyway!