Board Thread:Questions and Answers/@comment-5755346-20160429204719/@comment-71.83.236.251-20160430110827

Actually, 500 to 1000 units might be a pretty decent sum of prana. Saber herself has about 1250 units under Shirou, and though she's weakened she's still a freaking Servant. If we use the F/SN base of 25 units for the average magus, rather than the 40 for the Ciel specific example, than beings around the average Servant, Dead Apostle Ancestor, and Phantasmal Beast might have prana equal to 2500 units.

Touko is said to have B+ in Quantity of Magic Circuits. Since she has 20 circuits, if we connect this to the Servant parameter system where 1 = the average person's value, than the average human has 0.5 Magic Circuits. Next we have Aoko, who has C in Quantity. This extremely average amount, which we can thus call the average magus amount of Magic Circuits, is 15 Magic Circuits.

Shirou has 27 Magic Circuits, an unexpectedly high number. They can only handle 10 prana units though, a low number. Combined that should be 270 prana units. It's said his prana is 20 to 30 though. That is either referencing his F/SN current ability while 270 is his full magus potential, or we should deflate 270 to fit in the 20 to 30 as a 27 value. If we do deflate it, that means Shirou has about a 1 prana per Magic Circuit. If we continue with the average magus example of 25 prana total, having a 15 Magic Circuit count, then we get 1.67 prana per Magic Circuit on average for the average magus.

Considering this, Rin should have a 5 to 10 prana per unit if she does have 100 Magic Circuits and either 500 or 1000 prana total. Technically she has 40 main circuits and sub-circuits with 30 each, the subs probably referencing to her Magic Crest. It still is abnormal that she has such a high prana per circuit.

My thoughts on this is that Magic Crests are exponentially increasing the prana. Magic Crests are similiar to Magical Beasts in that they attempt to age; while no magi family has reached a similar status, Magical Beasts have aged so much their bodies have become akin to Magic.

It's said Kayneth Archibald has 3000 MP in comparison to Waver Velvet with 5 MP. Waver has the lowest quality circuits and crest as a 3rd generation, while Kayneth is the 9th generation of the Archibald. If we suppose Waver does have 5 prana due to his family's non-serious attitude towards magecraft, the average magus 25 prana, and Kayneth 3000 prana, then Kayneth has 125 times the prana of an average magus. Rin, the 6th generation head of the Tohsaka family, only has about 20 to 40 times the prana of an average magus.

While I am grasping at straws a bit here, the Magic Crest exponential value is my explaination to the nonsensical highness in prana for those with old families.