Responses
Yeah, at the same time though, before all of the weird stuff went down, Ikurou (studious) was jealous of Izumi's (slacker) natural ability to do well and get good grades. So Izumi idolized him, maybe a little too much and in a not family type of way, but Ikurou telling him to "be dumber than me" and then letting it get to his head when he started to do better than Izumi was a little off kilter, too. I kind of didn't like either of them. Ikurou with his jealousy/ego and holding his brother back, and Izumi with his freaky obsession, but at the same time, I feel bad for both of them too.
for people who say they don't feel bad for the older brother, i look at it this way; it's a lot of responsibility for the older brother to carry his brother's feelings around when he didn't ask for them. He's had a whole lifetime of being Izumi's object of affection (forbidden object of affection, at that).
It's also a sensitive age for them when they are supposed to be carving out their own identities, which must be hard when you have someone identical to you surveying and copying your every move. It must be the reason he clings onto their respective "roles" so much (I'm the studious brother, he's the slacker). Plus, they obviously live together, so there is no reprieve for the eldest brother. It must be maddening and still frightening after all these years.