Bartender - Vol. 7 Ch. 54 - Ryuu's Past (Part 1)

[MangaDex]

 

[Valle_reading_manga]

Is that supposed to be a German flag

 

[Vsmit]

Is that supposed to be a German flag

It is. It's the flag of the German Empire, used until the end of WW2.

 

[Valle_reading_manga]

Oh right, didn't make that connection