¿Did you draw this or did you find it online?, if you didn't draw it please tell me the creator, ¡it's so good!

↑ this is official art made by Seita Inoue

Thank you @ian so much for telling me it's creator and source, I wouldn't have found it in a million year's, when I tried reverse image search it only gave me one result.

I think this art is shown at the end of The story mode??

i found it on a youtube video of splatoon songs.