Kathryne Keyron card...

[Adrillf]

It is the cast time that it is reducing, not icreasing your dex.

SO, with the situation that you have above, you have to think about the spell that you're casting, we'll stick with storm gust for the easy math. SG, has a cast time of 15 seconds, each 15 dex reduces cast time by 10%, so with that dex, you're reducing it by 91.3333% which results in reducing your cast time by 13.7 leaving a cast time of a cast time of about 1.3 seconds.

The card would then take THAT CAST TIME, not your core cast time, but this post-dex cast time, and reduce this by 10 (if put in a +10 item) which would reduce it by .13, which would make your cast time 1.19 seconds.

Any questions?