Board Thread:Naruto Discussions/@comment-1018594-20160409062530/@comment-734582-20160418111410

The Kisame/Itachi thing is actually pretty interesting.

Kisame betrayed his comrades and stayed loyal to his village. Itachi betrayed his clan and stayed loyal to his village.

Itachi discovered Obito on his own, whereas Obito showed himself (or something) to Kisame. Itachi never stopped being loyal, whereas Kisame gave it up for Akatsuki.

And as OP mentioned, Kisame stayed loyal to the end whereas Itachi never was loyal to it to begin with.

EDIT:

i actually checked, Deidara's arm was indeed sucked up completely by Kamui. So Tobi could only have found it inside the Kamui dimension