In the Odyssey, which spans 20 years, Ulysses driving force is to return home with his beloved Penelope. Tucking the disastrous Trojan war into one corner--to which conflict Ulysses didn't want to join in the first place, but he was tricked. As king of Ithaca, subject to the vow of all for one, he had to back up any war declared by any Greek king. King Agamemnon's brother Menelaus lost honor when Helen ran off with Prince Paris of Troy. Only blood would wash away the dishonor.
Ulysses feigned madness to get out of going to the war. Having yoked a donkey and an ox to his plow, he plowed a field with salt--basically killing anything for further growth for years until the salt left the earth. Palamedes, at Agamemnon's request, figured wily Ulysses was feigning. He placed Telemachus, Ulysses's infant son in the way of the plow. Ulysses stopped and admitted his madness was a ruse. He went to war.
Ulysses' Trojan horse idea ended the decade-long conflict, but getting home took another ten years. Blinding the Cyclops, Polyphemus caused his delay as the Cyclops are sons of Poseidon. The sea god followed his blinded son's request for vengeance and Ulysses came home alone, all his men dead, having lost everything.
Did Ulysses change? He started out not wanting war, he tried everything to avoid it, but when the time came, his ideas changed the course for the Argive victory. He was no coward, but he knew there are other ways of changing things than killing and killing. In that he was right, up to a point.
Ulysses came home nearly naked, scarred, unrecognizable except by his old dog who died at his feet. His old nurse knew him by this. He took his son into his confidence.
Penelope was besieged by suitors who had insisted she take a husband rather than wait on a dead man. His son, still a minor, was treated like a servant and not as his father's heir. Ulysses disguised as an old man by Athena, noted the dishonor of these men to him as a king and to Penelope as their queen.
Penelope had tried to hold them off by weaving a shroud for Ulysses during the day, unraveling the threads at night. This worked until a maidservant betrayed her mistress and the loom was broken, the shroud burnt. Meeting the old man who gave a loving account of Ulysses quest to get home, Penelope made a decision. If any man could bend and string Ulysses' bow, and send an arrow through the eyes of a dozen axe heads, he would be king and have her as his queen, along with all the lands and wealth Ulysses' had.
Penelope had it set it up, she also had all weapons removed from the rooms, then she and her maids and household locked themselves away. The suitors mocked the dead king and each boasted of having his queen. No man had Ulysses' strength and all declared the bow cursed and the task undoable. The old stranger nocked the sting, he sent the shaft true. The noble suitors turned to kill him, Athena's guise fell away. Ulysses paid back the foul deeds and the greedy suitors in blood, returning honor to his home.
Did Ulysses change? All he wanted from the get go was to be with his family. He tried to make peace before the war, he tried not going, he tried faking madness, he followed Agamemnon and did all he could to end the conflict, because he wanted to go home.
Despite the action, the adventures, the angst, that's secondary to Ulysses' motive, his goal, of being with his wife and son. Of course this discounts Ulysses screwing around with women captives, or Circe, or Calypso. Despite these dalliances, Ulysses wanted home above all.
The character changes no matter what--whether we plan on them having a 'duh' moment or a life-shattering epiphany. By the end of the book, they've gone through some medium to heavy duty sh*t and that's been stretched out over days or decades.
A major assh*le can ease off a little or become even worse and out villain the villain. A person with a sunny disposition can fall into stupor or become psychotic with a 'god wants it that way' approach to everything, denying any responsibility for her life. One character can believe something about herself even more so: I'm not lovable becomes why should I try anymore. Or the MC builds shells around herself with each disappointment, and even each victory, as if she didn't deserve what came. By getting harder inside she's stronger for an even more fateful outcome later.
Frodo found an inner strength he didn't know he had.
Little Red Riding Hood--in a lighter version--nearly lost her beloved Granny if the woodcutter hadn't stopped by to chop up the wolf.
Change will happen, that's the nature of change.