Using the approach described in the guide, I had my first nightmare win yesterday.
http://te4.org/characters/30630/tome/c5 ... c835a6b660
Things pretty much went as described, even though the difficulty was lower. My main changes were:
- I only found one item with reduced spell cooldown in my run (boots). So I had 60% cooldown instead of 50%. As the guide says, this is a pretty amazing stat.
- I tried out barrier and found it to be very nice for me. I was initially just talent point scumming 3 points into it, but eventually decided to keep it at level 4 for high peak. What I particularly liked about it was the shield has a much longer duration, so it was easier to manage it and still get ridiculous shields when combining it with bathe in light. (I also had it on "autocast when no monsters visible" mode, so I would never get caught without a shield up.)
- On a related note, I didn't particularly stack +heal, especially at the end. I had some +heal for a while, but towards then end it got shelved as I was seldom using arcane reconstruction.
- In the early game, I was shockingly fragile. This was the cause of my deaths. They were typically "killed in two moves when I was not paying attention." I think I had one death in midgame due to overconfidence, and no danger in late game.
- I usually rely heavily on autoexplore and move with the keypad. This didn't really work for the archmage, as the desired way to start to a fight was to corner snipe with fireflash. Also I didn't want to be at 100% mana because a surprise fight would often end up with Disruption Shield getting cancelled. (Another reason I liked having barrier on autocast when nothing was visible.) I switched over to exploration with Vision, Arcane Eye, and Track, and used the mouse to move from area to area.
- Even if you don't get a lucky item with track, you can make do with a wand of clairvoyance, which are quite common, have a decent range, and a short cooldown. I did this until I found Fortune's Eye.
- The final fight was very easy, probably the easiest I can remember. I opened it by putting Elandar inside a stone wall, and rushed around closing portals. After that the sorcerors were focussed on Aeryn, but she stayed up quite easily through a combination of her heals + my disperse magic and bathe in light. My biggest problem was running low on mana.