* Αδέλφια στις μάχες (Adelphia stis mahes): This is a literal translation, meaning "brothers in battles." It's straightforward but might sound a bit stiff.
* Συμπολεμιστές (Sympolemistis): This translates to "comrades in arms" or "fellow soldiers." It's a more common and natural way to express the idea of close bonds in warfare.
* Ομοιοπαθείς (Omoiopatheis): This word means "like-minded" or "those who share the same feelings". It could be used to emphasize the shared experiences and loyalty between soldiers. However, it's less direct about the fighting aspect.
* Πολέμιοι αδελφοί (Polemioi adelfoi): This means "warring brothers," which works if you want to emphasize both the kinship and the combat.
The best choice will depend on the specific context and the desired emphasis. For most situations, συμπολεμιστές (Sympolemistis) is likely the most appropriate and natural-sounding translation.