Kramer
Don't see much on here about him, but I found him interesting. He isn't around long, and is really just more fodder for Eastwood and Burton, but Anton Diffring manages to do a lot with what little he's given.
What we do see of Kramer paints him as being surprisingly reasonable for an SS officer. In most WWII movies, the story goes out of its way to contrast, very sharply, the conduct of the SS and the regular military. And here, we certainly do have stereotypically nasty SS guys, but Kramer is different. Consider the following:
1. I think the edelweiss emblem on his greatcoat signifies that he's Waffen, rather than Allgemeine SS. The edelweiss being the symbol of the Gebirgsjäger (anachronistically referred to here as the Alpenkorps) means it's either a costuming error, or Kramer is in an SS mountain combat division. The novel describes him as "deputy chief of the German Secret Service," implying he's SD or something, but his edelweiss and his attitude towards von Hapen and the Gestapo in general suggest otherwise.
2. Not only is he good buddies with Rosemeyer, but he agrees that Carnaby's interrogation should remain "an Army matter," with minimal involvement from the SS, despite he himself being an SS officer! Unless he's doing this specifically to spite von Hapen, this means he's the only SS officer in movie history who actively wants to foster cooperation between his organization and the Wehrmacht!
3. That odd scene in his office where he catches von Hapen snooping in his private files. The conversation they have, and the accusations made, are strange, such as when von Hapen says "I know your loyalties" and him accusing Kramer of trying "to discredit me with my superiors in Berlin!" It's that first bit that is the most interesting. What does he mean by this? Does it tie into the above issue about Kramer seemingly wanting the SS and Wehrmacht to work better together instead of being rivals? Is he, somehow, despite being SS, anti-Nazi? Or is he pro-Nazi but hates the thuggish Gestapo?
As I said, Kramer isn't really important to the story beyond being just another German officer who gets killed, but we're given a few tantalizing hints about what kind of a person he is and what he thinks of goosestepping zealots like von Hapen. I would've really loved to know precisely what was meant by Kramer's "loyalties" and how/why Kramer was attempting to discredit von Hapen (besides simply hating his guts). Alas, the novel offers no new insights; there, Kramer is SD (but still shockingly reasonable) and gets along fine with von Brauchitsch (von Hapen's name in the book), so this enmity between them is a movie-only thing.
"I mean, really, how many times will you look under Jabba's manboobs?"