The official twitter account for ARMS in Japan has released a slew of character sketches straight from the development floor. They were all hand crafted by art director Masaaki Ishikawa and they depict great images of Spring Man, Ribbon Girl, Mechanica, Ninjara, Min Min, and Helix. All I know for certain is that ARMS looks more and more enticing as each day rolls by. We have the art available in our gallery below.
Source: Nintendo Everything