Cassie questions whether or not it is morally right to morph into dolphins. She is in awe of dolphin intelligence and wonders if it is okay to take the form of something that is so aware of the world and others in it. This theme of morality is yet another thought-provoking message that makes the Animorphs series so much more than just a moneymaking machine.
What always makes these books a bit more exciting is when we are served up some Andalite realness, and we sure get that in "The Message." This is the book where Ax comes into play and becomes a key member of the group. Through the introduction of Ax and his revelation that the Yeerks aren’t only seeking to control humans, but destroy the entire planet, Cassie decides that it’s not about whether or not she gets permission from a dolphin to acquire its DNA. Instead, she realizes that without the ability to morph into all species, the entire dolphin race, and every other species on Earth, could be wiped out.
Introduction of a new Andalite character.
Introduction for young readers into issues of morality.