Roman god of war, counterpart of the Greek 阿瑞斯 and in legend the father of Romulus and Remus, the founders of Rome. The month of March and the planet Mars, 火星 in Chinese, are named after him.
Ancient Chinese astronomers called the planet 荧惑, roughly 'the glimmer that baffles', for its shifting brightness and path, and read it as an omen of war, as Rome did. 火星 'fire star' comes from the 五行, which pair red with fire.
memory
Three syllables - 玛 'Ma-' + 尔 '-r-' + 斯 '-s' = Mars. The 玛 (agate) opens many female and mythological names (玛丽 Mary, 玛丽亚 Maria); the 尔斯 ending is a stock rendering of '-rs' finals.