Where does “Kämpfer” come from?

Kämpfer (German) comes from French camphre, from Middle French champore, from Old French camphore, from Medieval Latin camphora, from Ancient Greek καμφορά, from Arabic كَافُور, from Malay kapur, from Pahlavi 𐭪𐭠𐭯𐭥𐭫 — lime, calcium.

Kämpfer (German): agent noun of kämpfen; fighter