Hello.
I made a new character some days ago. A shadow Knight. I was searching the forum for the build and I saw many build with Giant Ground Wave and Giant Ground Explosion. So i decided to max them aswell. Once I hit LV40 I realized that I can't choose these skills.
So my questions are:
Are they only obtainable from Dragon wishes?
And if yes do I have to make a wish every time I want to upgrade these skills?

These skills are only useable with Great Namek. You have to make a wish for GN then you can use them.

Ah okay thanks. But do I still have to put SPs in them?

its up to u. If u like to us GN

But I have to make a wish for GN and first after that I can put SPs in there?

yes..