Multispell is in my opinion the most powerful feat there is, if you first take three Automatic Quicken Spell. The reason for this is that if you make it so that you may throw enough deathspells, the probability of saving against such effects is rather small if you may throw loads of spells in a round. Using this combo, a x level wizard may almost certainly ANY y level wizard, taken he has not the same combo.
If you only fail your save on one, the probability of failing your save, throwing n spells in a round is: 1-((19/20)^n).
Now we find out how many spells you need to get the probability for saving 50%:
n=ln(2)/ln(20/19)~13,5
That is if you can pull off 14 spells in a round, the fellow has less than 50% probability of making the save.
Given that you can cast Haste before the combat starts and you win initiative, you now need 15 epic feats to be almost a god:
3 Automatic Quicken Spell and 12 Multispell... Specialise in necromancy, and there is a big chance that you may pull off 14 death spells in a round:
5 9th level slots, 5 8th level slots and 5 7th level slots, not including bonus spells for high intelligence, and you have chosen the Heighten Spell before 20th level.
Taken that you may want to improve this, alternate between Improved Spell Capacity and Multispell the next levels, and it will be even more difficult to save. If you are able to pull off 20 spells in a round, for example, the probability for not making the save is 64%
If you only fail your save on one, the probability of failing your save, throwing n spells in a round is: 1-((19/20)^n).
Now we find out how many spells you need to get the probability for saving 50%:
n=ln(2)/ln(20/19)~13,5
That is if you can pull off 14 spells in a round, the fellow has less than 50% probability of making the save.
Given that you can cast Haste before the combat starts and you win initiative, you now need 15 epic feats to be almost a god:
3 Automatic Quicken Spell and 12 Multispell... Specialise in necromancy, and there is a big chance that you may pull off 14 death spells in a round:
5 9th level slots, 5 8th level slots and 5 7th level slots, not including bonus spells for high intelligence, and you have chosen the Heighten Spell before 20th level.
Taken that you may want to improve this, alternate between Improved Spell Capacity and Multispell the next levels, and it will be even more difficult to save. If you are able to pull off 20 spells in a round, for example, the probability for not making the save is 64%