Captain Rahn is the anti-hitler captain who sits around doing nothing for 3 days while you sink 5 ships and conn the boat singlehandedly. And for this he is rewarded with U-1something or other. I'm only in Febuary 1940 so i dont know what happens to him.
He's anti nazi, so i'm sure he'll die, another attempted realignment of the nazi people's true moral compass :P (Almost half of germany was nazi in the mid 1930's, but according to SH5 by 1939 they are down to something like 4 or 5 percent
(only one person out of like 16 is an open nazi, one is "A bit racist".