CU: Would you believe me even if I told you what the nexus produces?

Thank you for the compliment, although it's mostly a feature of the undewater nations that they can tenaciously cling to life, rather than any supreme strategy... My greatest asset is selecting the most broken nation for the environment!
I participated in a game with a mod where the life-drain weapons had been significantly raised in cost (like, a blood thorn for 80 slaves); well, that didn't remove them, it only served to limit them to heavy blood nations, which in my opinion only unbalanced the game in their favor. Zen's solution makes them rather unusable for most anyone, which isn't cool either. Perhaps lowering their damage and attack would be a good solution (less than the ~20? points Zen has), since then a good armor or high defense would protect against them. Indeed, wouldn't lowering their attack value or damage by something like 5 points accomplish almost the same thing as Panther's proposition of removing the fatigue-gain? Only, instead of having to fit a reinvigoration item to the mix, attack boosters or strength boosters would need to be considered.
I haven't yet played a game with the item-mod, but I'm not sure if it's a good idea to have area of effect magical weapons especially with multiple attacks. As I understand it, with an AoE attack the hit is certain; thus these weapons make attack and defense values a non-issue, weakening all sorts of units that don't need any weakening and also strengthening astral weapon that wouldn't really need it. (Assuming astral weapon works with AoE attacks - I don't see a reason why not.) An always hitting, armor-negating ~40 point attack 4 times a turn should shut up most opposition. With a quicknessed golem and the morning star that gives 10 damage you can, assuming the above. (Undoubtedly with so high a damage bonus you wouldn't even need astral weapon, come to think of it, so a regenerating chassis might be preferable.) But this is just conjencture with no testing whatsoever, which I'm more than happy to try out in the next game Chris hosts!
