@Bluubuckets The president did have a hand in the parents' deaths, as did the families of the other bullies since they are all rich, influential people. They used their money and connections to downplay the bullying charges, and sent the bullies overseas to escape the public demands for justice after the parents' suicides. And now that the bully's dad is president, he's used his authority to clear the charges and pave the way for their kids to return to Korea as free people (not to mention the mafia connections the families/bullies have to likely intimidate others into leaving them alone).
@LuffyKun Yeah, there was a 1 year time-skip + a few months prior of his own sword training (push-ups, stair-climbs etc.). His drastic growth spurt and abnormal gains was probably due to inheriting the sword's previous owner's powers; think reincarnation.
Hoping the brutality will increase as he works his way up to the ring leader (who looks to be the guy with the girl who has white streaks in her hair).
I like that the handle within the blade is being utilized, and wasn't just for aesthetics.