In his Japanese name, 空操弾馬 (Kūsō Danma), his last name, Kūsō, consists of the kanji for "sky" (空) and "honor" (操). The first kanji in his given name, 弾 (dan), has a number of meanings: bullet, ball, pellet, and shell. The next one, 馬 (ma), is much simpler: it just means "horse."

There is a misconception with some English fans that "Kūsō" is pronounced the same way as the Japanese swear "kuso" (which is an equivalent of "damn"). However, in Japanese, the two words are quite distinct, as the hiragana for Kūsō would be spelled くうそう (the vowels are drawn out), while the swear word is くそっ (all vowels are short).

His last name is Kuso, you know what kuso means? crap/shit as an interjection.