I have several favorite characters so that choice is a bit hard to do, but I think the character that I love the most because I'm struggling and not simply for being the protagonist of the anime is the Eren Yaegar,is dedicated and is not the kind of hero cocky, he has flaws and often commits some crap I'm glad he has the Mikasa to correct him hahaaha...
Besides he is a very charismatic character and sometimes it's funny the way he impulsive sometimes weakens, and still can't accomplish their missions more always around giving a great checkmate in the Titans, it is for these reasons and because he's not perfect that I appreciate so much He's not the guy Russo, who saves everyone, every day he has weaknesses and defects and very amadure every chapter of the anime, so don't lose the grace and the other characters do not depend on totally him, because others also have great powers don't turn into Titans as Eren, but they're smart and strive to perform foolproof plans but my favorite is this boy who sometimes is weak and sometimes so strong, the boy who promised to avenge the death of his mother and exterminate all the Titans from the face of the Earth.
My tattoo of Eren I did a week ago, was only the first session I can't wait to finish it and start the next anime tattoos I have in mind, I want to tattoo others characters from Attack On Titan might close the arm with this fantastic anime characters.
If I could choose a second favorite character would be the Hange Zoe, also the anime Attack On Titan, the nuts of the anime is extremely intelligent and cheerful features that make she conquer any attempt.