I think the first character I'll go in depth about is Sung-Min.

At least that's his assignment name. He went under multiple names and identities as he grew up. He has received rigorous training and the best possible informal education his Trainers could find.

He attended a disciplined martial-arts training school in China in his youth. Due to the nature of his studies and bionic abilities, he accelerated through the program and was pushed to move forward after three years (his trainers had decided that he had learned enough to progress).

He's lived in the rural areas of Thailand, learning to appreciate everything that life could offer while living and working on the remaining farms. He learned to make all sorts of traditional food from his homestay family.

He's lived in Hong Kong, captivated by the ever-sparkling, bustling streets. He learned English there, and attended his first regular school. The trainers thought it was important he interact on his own, learning how to adapt and react to other people.

He's lived in Kyoto, a traditional town in Japan. He continued attending regular schooling -- the trainers thought it would be best for him to interact with people his own age -- and picked up extracurricular activities which aligned to further his training (more martial arts, swordsmanship).

And finally, he was moved back to Korea to complete his training. He was more of an independent person by then, having reached the age of 17 and going through that "identity" phase quite a bit late in his busy life. He decided that he liked dancing -- it was organized and synchronous like most martial arts styles.

At 18, the four bionics were recalled to the United States to officiate their status as the world's newest line of defense.