Kefka vs Goku

[Sephiroth]

But knowing Goku wouldn't know the FF verse's stats and items too well hr might come a bit unprepared except for bringing his clothes on his back and his power and intellect (if it's that big). I think your scenario might be true since the rules of the FFverse don't apply to DBverse. But I remember one guy saying on DBZ forums that if Babidi the wizard who revived Buu was a fighter with the magic he was able to use, he'd probably the deadliest enemy they ever fought. Buu was something but his magic knowledge was limited to turning people into candy. Babidi had a far larger variety of magic attacks. So I guess a Babidi fighter would be a bit like Kefka in some ways.

Magic has always proven to be a 50:50 thing in Dragon Ball. Sometimes you resist, sometimes you don't. Also magic can be deflected. Boo counters the transformation magic, Vegeto is totally immune against being negatively affected by it as his candy form makes no difference for him, Babidi's mind control magic is useless for Vegeta as he is corrupted and stronger with it but does not follow Babidi's orders, et cetera. So basically it is all about the "if you are stronger than that you can resist it" again. And Dragon Ball characters are very resilient to magic that they do not want to negatively affect them. You would need someone who actually is shown to have really overwhelming power while wielding magic. Something Kefka was not shown to have. He devastated the landscape and made it infertile. Piccolo Daimaoh was able to use such destructive power already. Kefka's power is not fleshed out enough. Oh - and Boo is not limited to just making sweets.

You need to have power that is really shown to be overwhelming.

If we take X-Death for example he would be totally useless against Goku. The Void is not just shown like some space-time-less "thing" but also shown like a prison from which you can break out. Right before the final battle they do. And that makes the Void already another dimension even though it shouldn't be. Goku can break out of other dimensions. Boo and Gotenks also did. As a matter of fact Goku, Boo, Cell and others have even teleported between dimensions.

EDIT: Yes, I did draw it. Thank you.