幾重にも、幾重にも、その手を血の色で上塗りしていきながら、だが男は決して怯まなかった。
Can one use ながら and だが together ? this seems rather perplexing to me .
Yes, the combination of ながら and だが/しかし is used, but mainly in literary works. I checked BCCWJ and the majority of examples were from literary works. This combination is interchangeable with ながらも, which is already a stiff expression, but ながら+だが/しかし sounds considerably more "dramatic" to me.