Ga Kusha's name is pronounced the same as the word for "scholar" (学者,gakusha?), which also makes up the end of the word "archaeologist" (考古学者,kōkogakusha?), hence the misunderstanding by the New Royal Army.
This pun is preserved in English by translating his name as "Ska Lar", similar to "Scholar".
References[]
↑ 1.01.1One Piece Video Game — Odyssey, Reunion of Memories, Ga Kusha makes his debut.