>.>
What's the flag on this? Stolen would be my guess and my quick searches came up with mostly a lot of nothing save two relevant accounts, one at maple story, and another at some game site that showed nothing other than a person with the same account name (in this case safe to assume the same person) that happens to be fairly good at games.
Which leaves only the possibility that using his print-screen technique to rip maple story characters even for free entertainment violates copy write (they don't operate under any sort of free-use license in their various forms). A review of their copy write disclaimer and their TOS makes it plain that they do not allow it therefore (although I hate to see an amusing harmless bit go) I am inclined to say this is stolen.
However the entire situation is a bit strange seeing as how the bannedstory site itself has no provision of the legality of posting your creations using it, but why should it seeing as they are operating provisionally, and even encourages (well, at least points out you -can-, notice I say can not may) load the sprite icons frame by frame into animation software, we're left with the rub of direct listing of the legality (copywrite wise) of posting said creations on another site, only the pre-existing, and generally assumed to be all-encompassing copywrite notice of maple story itself that no images may be used without written permission to the contrary for any purpose, I honestly dunno if the existence of this software constitutes permission >.>.
Also if the whistle was originally blown because it was stolen from someone else (e.g. not the company) my little investigation of sorts didn't retrieve anything.
Ultimately I was inclined to add my whistle to the batch (normal little thing that it is) and rather just hope that this entire thing is side-stepped, as while this not a great animation, it is amusing and at the very least I'll have been glad to see it once or twice now than to never have.
A note to the author, try contacting maple story for permission (you could get lucky).
Ciao ^.^