Ah, so a Zonpakto is something that resides in your mind and gives you power!
Assuming you don't get beaten up by your evil twin.
I love that speed motion effect, I'm wondering how you even did that.
Ah, so that Skakdi headed thing is the form used under the control of HH! Makes sense.
Now for some constructive criticism.
Good work on the rotation, but either you forgot to set the threshold to 0 or the sheet itself is not pure white background, and you'll need to find where and fix it. That's why there's a bit of white excess left.
When you're scaling something up like the last panel, use Paint rather than GIMP. Also, don't stretch the box. Right Click>Stretch/Skew>Type vertical and horizontal percents (make sure they're the same or it will look stupid)>OK.
So if you want it 2x bigger, 200%. 3x bigger, 300%. And so on.
And for sword swings and simple stuff that don't require the DBZ/Naruto/Bleach/Action Animes In General motion effect, use the smudge tool for a bit of motion blur, otherwise they look like they're not even fighting and are just touching swords.
If the characters have extreme super strength or something, it's also wise to put each character on a separate layer, then put a layer between them and put sparks in the clashing metal. However, since that only happens when there is sufficient force, it is not necessary unless they have above-Matoran strength.