Note: I have only read up volume 6, chapter 49, so if any explanation for Akito/Agito's personality arises I have not read it yet ;
Description: A look at Kaitou's and Akito/Agito's relationship as brothers.
When they were younger, Akito looked up to his brother with blind devotion. He sought to emulate everything his brother did. As Kaitou started to grow out his hair, Akito did the same. However, with long hair the younger perpetually had it caught on one thing or another. On the day Akito returned home with grass and leaves tangled in his hair Kaitou insisted on having it cut. After some pleading, Kaitou relented and allowed his younger sibling to have shoulder length hair with the condition he kept it neat.
Once Kaitou took up air tracks Akito wanted to learn, too. But his brother told him it was too dangerous and forbid it. As Akito watched Kaitou fly through the sky, his desire to follow his brother deepened. But Akito was not one to disobey his brother. He was torn between the desire to take to the air and his desire to comply to his brother's wishes. From this inner conflict Agito arose. With Agito's fierce determination to become the strongest, Akito sat back and enjoyed the feel. It was the feeling that he could do more then just copy his brother, that he could possibly even surpass the
Kaitou learned about his brother's participation in air tracks and he was furious. His brother never disobeyed him before. As he tried to force Akito to stop, Agito took over and said he would only listen to someone who could beat him in a race.
The course was set to be from their home to the library several blocks away. Agito left his brother far behind. Kaitou grew to hate air tracks, the thing which brought this foul-mouthed and violent person he did not recognize as his sibling.
Akito silently rejoiced when Akito defeated his brother. Even though Akito was not directly in the challenge, it was still his body and he felt some pride from that. He also realized that he had fallen in love with the exhilaration of air tracks. The freedom of movement he felt was breathtaking. This was something he would continue doing no matter how much his brother opposed.
Still, Akito remained with his brother because he loved the brother from memory, the one who did not so hate air tracks.
As Akito met Ikki and saw the man's wings he was reminded of his brother, who once soared as a bird.
End Note: I just wanted to find a reason for why Kaitou now hated air tracks and why Akito had a split personality, no other reason aside from those :)