ZIPMAN!!

Zip up and get your robot on! A new type of robot-action series! World-famous handsome mechanical engineer Koshiro Tatara and scary-looking musclehead Kaname, these polar opposite twins both fell in love with the same girl's smile. Since then, they compete daily to see which of them can make her smile more. But one day, tragedy suddenly strikes Koshiro... A new robot battle action manga with a totally unlikely duo from Yusaku Shibata, creator of Yoakemono!
(Source: Manga Plus)