I could say that's fan-art. But it's more like just drawing extruded in to 3d- mesh. The topology and polycount isn't very nice, but the main point was to create a 3d model, which looks like hand - drawn image . Based on this , original design by Yō Yoshinari: http://goboiano.com/wp-content/uploads/2017/02/tumblr_nyghnpzl7S1qmlmyuo4_1280-1024x718.jpg Colours , and shape of character is in 95% exacly same with image.