That aura for the Bleach wall really does look odd and out of place there. It also looks low in quality so you might
want to remove it and focus on something else. If you wish to keep something around Zangetsu, maybe a more abstract-like
approach would be better - you can check out these wallpapers - 1 and 2 to see what I mean - things must not always be scenic. I would
also suggest to revise the colored image of Zangetsu because right now I can see some jpeg artifacts (pixelation and
blurriness) which takes away from the quality of the image, especially on his shirt - try to vector the outlines and
colors, I think that would look better.
As for the Shanks wallpaper, the image of Shanks looks pretty okay but the background is too simple, repetitive and
lacks effort - here I think a nice scenic image like the sky and ocean with some islands in the distance would look much
better. That skull is also not necessary since it takes the focus away from the main character...
That's what I have so far, I wish you luck with them!