Avatar the Last Airbender 0

[carter3175]

Does anyone here know the 1st app in comics?

[Qalyar]

If you count comic appearances in a magazine-format non-comic-book periodical, then the June 2005 issue of Nickelodeon Magazine. If you want an actual, fully-dedicated comic book, then that's probably the 2007 mini comic pack-in with Book 2: Earth DVDs. If you want a standard format comic book, that might be as late as the 2011 FCBD issue, but not certain.