Interesting. And crazy. Lots of crazy. So Gen killing Masaharu had nothing to do with saving Reiji; in his mind, he wanted to erase the moment in that closet, which he would be reminded of every time Reiji would get a beating. So he killed him. I mean, it freaking crazy that Yuko manipulation was to this extent. Even giving him a handjob in the closet to get his adrenaline pumping. But even after killing Masa, he still couldn't forget, esp when the neighborhood boys bring it back up or Reiji giving his thanks and appreciation for it. I gotta admit, when Reiji called him out a couple dozen chapters back that he didn't love him, but instead, loved Yuko, I thought Gen was done; Reiji gave him the psychological slap that he'll never recover from. I'm actually impressed the author was able to pull even more insanity from his story. He's still no more likable than before, but it does paint him in a more sympathetic light.
I'm guessing due to the trauma of killing Reiji's dad and Yuko's manipulation throughout his life finally broke Gen; and now that has harbored such a fixation on Reiji due to all that I'm assuming he has some feeling of wanting to replace Yuko as the thing Reiji is returning to. Speaking of Yuko, where did she end up at the moment?
Reasonable analysis =03. People thinking Yuko dead, but I say there is no way that Yuko will go down without Reiji getting that confrontation. Being the most direct influence to all the events he's been through most of his life, not to mention all of the s**t she's fenagled through, I can't see her going down just from this; its likely she's hold up in her room and might play the damsel in distress when she re-reveals herself.