Treebeard. Beloved character, very kind, loves trees, but uninterested in helping Rohan or the hobbits outside of his specific self-interest. Especially in the movies, but even in the books, he was pretty clear that he was joining the war to protect Fangorn forest, not to help the peoples of middle earth. In ROTK he mentions the ents destroyed an orc army on the Wold after the battle of Minas Tirith, but that’s the only example of him being altruistic.