Tabisu
I honestly don't believe this is your art.
[1] The styles aren't the same.
[2] Your second piece is a "thank you" image for undoubtably the true artist's deviantART or webpage.
[3] The details you give are sketchy at best.
It's offensive for you to post other people's work and claim it as your own.
It's also against Gaia's TOS, and it infringes on the rights of the artists.
If you want any true artist to actually, legitimately believe you, you should set up a gallery with work consistent to your claims.
I refuse to believe this work is yours without any sort of proof.
I kinda agree none of them look alike and the one of Itachi looks just like the picture i repeatidly see on the internet and doesn't look like you drew it.
And the second picture looks like another picture I found which I'm sure it's by someone else. None of the styles look alike what so ever and I would feel ashamed if I stole someone elses artwork and showcased it as my own. That's how'd I'd feel anyway.
I admit you said your friends drew some of these, but you should atleast say which are yours and which are not.
Please if these are not yours, take them off for the artists sake people do not appreciate it when others claim their work for themselves. I know I would feel horrible if all the work that went into my art had been taken from me. As a fellow artist please if these are not yours show yours and people will give you advice they will not tell you your art is worthless and if someone does you can report them or delete their comment. People will tell you how to make your drawings better. I don't mean to sound rude, honestly, I said this as nice as I possibly could, it's not to sound offensive.