Light Manipulation: Ken is capable of creating(Although creating light is far harder than just manipulating it, and thus takes up a lot more stamina) and manipulating light. Due to how broad his power is, light manipulation can be used for any number of things. From creating solid constructs to blinding people, it's ability is only hampered by his own imagination and willpower. He's too scared to use it though, since if he expends himself too much, he coughs up blood.
Personality
Ken is somewhat outgoing, despite his serious exterior. He tends to not really take things too seriously, choosing to just 'go with the flow' instead of spending his time worrying about things. Ken's also pretty open, and doesn't hide things from people. He's a pretty good person, all things considered. Though he does lack motivation and often fails to grasp the gravity of situations, especially social ones. A bit dull.
Background
Before Ken got powers, he was a pretty insignificant person. He lacked motivation (still does) so he really just coasted by. However the whole set up got fucked up when he developed superpowers. Kens family wasn't too accepting of his gifts. In fact, they thought about putting him up for adoption, but soon decided that they didn't hate him that much, or perhaps they just didn't want to have to pay for it, since they figured he wasn't worth it. The world will never know. Anyway, they settled on boarding school and after much trouble, they found Pakora Academy, an academy that accepted all sorts of freaks and monsters, with no sort of discrimination! The perfect place for him. So, he was immediately made to pack his things and be sent off to the academy, where he'd spend his days until he graduates. Luckily, he didn't care too much either way. He'd be fine in a new environment, he was always okay at making friends. Although he would be very uncomfortable about being around people that have powers, as he tended to not like confrontations, and only could imagine what sort of crazy fights could arise from super-powered highschoolers.
And almost every harem anime takes place at a boarding school