I'm thread-jumping from the shamanism discussion here! On that thread, I worked out how many spells a sorceror could keep up all day, but I got the rules wrong
gran_orco said:
Meanwhile, shamans of my group will play with only a pair of spirits of 1 use while sorcerers and other magic users have 5-6 permanent spells... a sorcerer can do a spell like FLY or DAMAGE ENHANCEMENT many times spending only 1 mp, again, again, again...
Here's my incorrect example from there:
If he has a POW of 16, say, he can do that 32 times in a day without overly diminishing his MPs. With a Manipulation skill of 65 he can make it last 3 hours, so yes, he can keep one spell up all day excluding sleeping time. If he casts all his spells independently, he can keep up 5 spells for 18 hours a day by using all his MPs. So, I guess it is possible, but that leaves nothing left for casting any other spells. Some spells can only be cast together with Combine, though, and that reduces the duration while keeping the same MP cost.
I now notice that this is incorrect in two ways. One is that his spells only last 2 hours (128 minutes) not 3 hours. The other was assuming that a maximum duration spell cost 1MP, as per the rule:
p47 said:
sorcery spells cost as many Magic Points to cast, as
the number of manipulation components applied to it; with a
minimum cost of 1.
This rule is incorrect, the correct rule is:
p129 said:
Magic Points
Sorcery spells cost 1 Magic Point plus as many Magic Points as
the number of Manipulation effects applied to it. Jedekiah, for
example, casting a sorcery spell upon himself with no Manipulation
uses only a single Magic Point. Applying five Manipulations would
cost 6 Magic Points (one for the basic spell, plus one point per
Manipulation).
If you take it as just doubling the cost of each spell, then clearly he can keep up half as many spells. 5 would deplete his MPs by 7⅓ every 2 hours, so he can only do that twice. 2 Spells cost 4MPs, which leaves him ⅓MP short per two hours, which leaves him with 12MPs by the end of the day.
If instead you use Combine to cast the spells, you can get 3 spells for 4MPs. 1 for the basic cast, 1 for the Duration, and 2 for the two additional spells. However this reduces the duration to 96 minutes, and in that time he only recovers 2 MPs, so now he's losing 2MP per 2 hours, so by the end of a 12 hour day he's only got 10MPs left. Cranking that up to 5 spells all day with Combine means he's re-casting every hour (well, 64 minutes) and spending 6MP each time, recovering only 1⅓ MP, meaning he's out of MPs in under 4 hours again.
So, sorcery may be powerful, but keeping more than two spells up all day is simply not possible at normal human levels. One solution to this is to transcend normal human levels with Enhance INT and Enhance POW, so all your unmanipulated spells last twice as long and your skill goes up by somewhere between 23 and 36% giving you up to four additional Manipulations on top.