[Kallatari]

I'd build it as follows:

Energy Reserve (Magic Cost Reduction) 1 [3] + Regeneration (Very Fast, 1 ER per second; ER for Magic Cost Reduction Only, -0%) [100]) = 103 points

That effectively reduces the cost by 1 as you use the mana point and regain it immediately next turn. To reduce it by 2 or more it gets more complicated, as the next level of Regeneration is Extreme, which regains 10 ER per second and is worth [150]… so it's roughly 5.5 points per extra level. I'd go for 2 per second at 110, and then +5 for each extra point until your reach 10 per second at 150. This makes it ER 2 [6] + Regen (2/second) [110] = 116, then an extra +8 per level after (3 for ER and 5 per level of Regen). Regen technically stops at 10 per second, but if you want faster, I wouldn't see a problem with the +5 per extra point each second is fair.

Note, the Regen only affects this specific ER, and wouldn't affect the regular Mana Points reserve that mages might have.

So, my final cost:

Option 1: Magery Spell Energy Cost Reduction (103/116/ +8 per additional level)


Someone else had another valid approach of Magery 5 (Only for purpose of reducing spell cost, -40%) [30], giving a final value of:

Option 2: Magery Spell Energy Cost Reduction (30 x level)

This method is cheaper for the first 4 levels... then becomes significantly more expensive than the first method.

While the second sounds more reasonable off-hand for lower levels, I think overall power-balance-wise the first approach is more fair when you consider how versatile and powerful this is (you only need 1 level to cast a whole lost of spells for free, as most mages will have at least skill 15)... but that's just my opinion.