The Dink Network

as i've levelled up, casting the thunderstrike magic is costing me more and more life. it's gotten to the point that i can only cast it about 6 times and them i'm out of life. the boat repair kits used to cover the cost of a cast and a little more, and now they are not even sufficient to cover a cast. why is that? my magic stat is 23, is that too high? is there any stat i should improve to have it not hurt me so much? my defense is only 14, but that goes down to 10 on the water anyway.
any help is appreciated!

It's because your luck is so high. But the good news is that it does more damage to your enemies too. If your magic were higher, that would cut down on the damage you take.

Higher magic = higher magical defense, as Paul pointed out.

But I don't see how higher luck causes it to do more damage?

Because when you attack, the attack damage is from a range, say it's 10-15. If you have high luck then it's more likely to be 15 than 10.