Kokai always looked younger than he actually is, his face has always had this roundness to it that never went away, even in his eyes, which were also remarkably big, seemingly sparkly with the joy of a child and of a grayish green color. His brown silky smooth hair has always contrasted with his slightly pale skin and eyes. His height of 148 cm and 42 kg didn't help in making his whole physique look quite right for his age. His regular attire are sports jumpsuits of different colors, typically red or blue, on his house however, a simple pair of cargo shorts and t-shirt is his choice of attire.
He is a lively boy, always looking for stuff to do and hating to nap or rest unless night has arrived. He doesn't mind working hard for something if it's in order to improve himself or help others. He is indeed very happy, but that happiness comes from a naivete, which also makes him prone to pranks or people taking advantage of him, also he thinks everyone deserves a second chance. He isn't the most self-preservating person, as he's willing to put himself in danger to save others. Murder is also off-limits for him.
Kokai was raised by a single mother, the widow of a deceased Shinobi, Kokai's father, who served his village with unwavering loyalty. He however died when Kokai was merely 2 years old, but his memory lasted in the form of tales Kokai's mother would tell their son everynight. The boy grew absolutely adoring such stories, how his father was to his eyes a paragon of justice, a hero who sacrificed his own life to save a fellow Shinobi, and he set his mind on becoming one himself. He saw it as becoming a superhero, so he definitely had to train harder than he ever did, and so a tendency of him was born, running everywhere! (Along with excercising everyday), which eventually made his mother gift him a handful of jumpsuits for him to wear.
Now, he just can't wait for that day where he will be able to go in missions and help other people! However, he's absolutely not prepared to learn the true nature of Shinobi, the ruthless killing machines they can become, and that some people on this world are just beyond saving.