Some sweet stuff you've got there Masa! The rounded corners are kind of your trademark. I especially like the Minamimoto, Frankenfran, Korra and Crazy Vampire sigs, the composition of the different elements is very well done in these!
One thing that caught my attention is that the renders/stock pictures seem to be stretched in some of your sigs and avatars. I guess you wanted to make the renders fit the dimensions of a typical sig/avatar? I used to try that too, but personally I find it better to do it the other way around: Make the avatar/sig fit the render. I use different canvas sizes with different aspect ratios depending on the render I plan on working with and sometimes I also end up cutting or expanding the canvas midway through the creative process.
Was that explanation understandable? I'm so bad at explaining things and finding the right words :katcry:
Any text on the signature? Like a name/quote/etc?
Also any filter preferences? (Color or design overlaying the picture)
Ive never seen the anime so I'll have to look up some stuff that goes well with him