YMMV / The Immortals

• Alternative Character Interpretation: Daine asks whales to attack an enemy fleet. The whales - a pod with calves - listen to her but refuse on moral grounds and because they don't want to kill and die for her, like the other animals she calls do. Daine is enraged and says that those animals fight for her because they're her friends. Most animals do what she wants immediately and with little regard for their own well-being, including ones she's never met - are those her friends, or does her magic overwhelm their self-interest and drive for survival? She doesn't like when animals get killed for her but the few that aren't immediately eager to please - whales, rats - make her angry in a rather entitled way. She's still sore about the whales in Tortall: A Spy's Guide.
• Anvilicious: Wolf-Speaker is quite a short book but Daine gets very similar advice in it so often that she ends up hanging a lampshade on it - ever since she's come to the Long Lake valley, she says, people have been telling her not to make snap judgements about anyone she instinctively dislikes.
• Aluminum Christmas Trees: "Duckmole" is not Call a Rabbit a "Smeerp"; it's one of the words that the English coined for the platypus when they first got to Australia.
• Harsher in Hindsight: Wild Magic has pretty Black-and-White Morality. Good people are nice people and nice people are good people, maybe a little grumpy at worst. Later written novels are harder and more pragmatic. Those can cast the scene where Jonathan sits down with Daine in a less pleasant light. As a thirteen year old with limited experience in the wider world she doesn't understand that there are machinations at work and Jon is doing his best to charm her and persuade her to work for Tortall - if she and her mysterious powers leave at this point, having had a close look at how the Queen's Riders function, and go to lend themselves to some other country, that would be a real liability. Of course the Tortallans are invested in making her want to stay.
• Never Live It Down: Daine's romance is controversial. Age-Gap Romance is an Author Appeal for Tamora Pierce, but Daine being sixteen when she gets with her thirty-year-old teacher Numair makes a significant subset of readers uncomfortable. Enough readers objected that Pierce said she would write smaller gaps in the future.
• Paranoia Fuel: Whenever Daine gets upset enough, animals in a huge radius instantly respond to her will. If this means getting themselves killed, so be it; her magic makes them disregard everything but her needs, even if they've never met her. Very few animals seem to even be willing to resist, and Daine actually has to consciously force them not to make suicidal attacks. Beloved animal companions will turn on their people without a thought if she's angry enough, and in this pre-industrial society where there's emphasis on the bonds between people and their mounts and dogs, that's a pretty big deal. A strawman brings this up in the first book, saying that people can't trust her because their horses will abandon them for her, but no one gives this further thought.
• They Wasted a Perfectly Good Character: Each book is quite separate from the others and only a handful of characters appear in more than one - only Daine, Numair, and Kitten are present in all of them, and Alanna is at least seen. It's a contrast from Song of the Lioness and Protector of the Small, which has each book closely linked to the one before and after, and more like how Beka Cooper shows several well-spaced interludes in the life of its protagonist. Few characters are present for more than a book, and that's a bit of a shame as many of them are interesting.
• Too Cool to Live: Rikash Moonsword! The Immortal with the most Character Development and character in general, good but not nice, an honorable person in his way. Yes, Daine names her son after him, but Dead Guy Junior just isn't the same.