Adventurer and friend, Finch-Hatton serves the purpose of marking the narrator's time in Africa. Well, he probably served more of a purpose in real life, wink-wink, but that's just too hot for the pages of a 1930's memoir.
We really don't get past Denys' cool-guy front. Let's just say that he doesn't always drink beer, but when he does it's probably Dos Equis. There's not much that this dude can't do. When he isn't leading safaris or flying his personal plane, he's chilling at the farm with the latest books and music. He's also a genius, and teaches the Baroness "Latin, and to read the Bible, and the Greek poets. He himself knew great parts of the Old Testament by heart" (5.8.4). So he's a religious man, super-learned, and also a tough guy.
Oh, did we mention he kills lions, like, constantly?
Denys and I, whenever we were together, had great luck with lions. […] When Denys and I went for a ride, the lions of the plains would be about, as in attendance, we would come upon them then there at a meal, or see them crossing the dry river-beds. (3.8.7)
We're guessing that Denys Finch-Hatton was the prototype for ye olde Old Spice dude.
We hate to be gossipy (okay, we actually love it) but there're more than a few hints that the relationship between the Baroness and Denys leans romantical. For one thing, she mentions her husband once, in passing, just to say that he had left the farm. Out of sight, out of mind.
Then, she tells us that Denys practically lives on the farm:
Denys Finch-Hatton had no other home in Africa than the farm, he lived in my house between his Safaris, and kept his books and his gramophone there. (4.8.1)
That's pretty scandalous, for the early 20th century. We're guessing he left a spare toothbrush there, too. Denys is a VIP for the Baroness.
Flight is Denys' forte. He has his own plane, and often takes her up to see Africa as no one else could ever see it. He zooms over buffalo, to different lakes, and just for rides over the continent. No wonder she likes him. He sounds pretty swoon-worthy.
That high-flying tendency is also his end, though. It's kind of fishy, because towards the final section of the novel the narrator starts to talk about leaving Africa, and Denys suddenly gets weird:
Denys, who held himself to be an exceptionally rational person, was subject to a special kind of moods and forebodings, and under their influence at times he became silent for days or for a week, though he did not know of it himself and was surprised when I asked him what was the matter with him. The last days before he started on this journey to the coast, he was in this manner absent-minded, as if sunk in contemplation, but when I spoke of it he laughed at me. (5.3.17)
That's the first foreshadowing of Denys' untimely end, but things get even creepier. When the Baroness asks to go on his trip with him he refuses to let her, but doesn't seem to have a good reason why. He breaks a propeller in Mombasa, and then crashes and dies on his way back to the farm.
This death, and its terrible timing, just before the Baroness must leave, is like the door closing on her African life. However, she does take some time to memorialize the guy:
What [the people] really remembered in him was his absolute lack of self-consciousness, or self-interest, an unconditional truthfulness which outside of him I have only met in idiots. (5.3.36)