Mecha stands for mechanical (in this case, mechanical units or robots). Youâ€™ll never see a mecha manga without a robot or mechanical suit/object in it. Thatâ€™s the most important element of it. And while this genre is rising in fame as the days go by, it almost always uses a standard formula to carry the plot. As a general trend, mecha is often seen alongside the military, sci-fi, and action genre.