DEARKA ELSMAN SPOILER!

Dearka pilots the stolen Buster Gundam and initially treats the war with the confidence of a talented ZAFT soldier who has never had much reason to question what he has been taught about Naturals. That begins changing after the Archangel captures him. Living among the people he had dismissed as enemies, especially Miriallia Haww, forces Dearka to see the human cost behind the slogans. Their relationship is messy from the start because Miriallia is grieving Tolle and Dearka was part of the force fighting them, but that discomfort is exactly what makes the shift believable. Dearka eventually chooses to fight alongside the Archangel rather than return obediently to ZAFT. He never becomes a different personality. He is still laid-back and sarcastic. He just stops letting that ease substitute for thinking about what the war is doing.