From what I understood from chapter 1, I thought he was dropped into this new world, but now from this chapter it seems he just possessed the original Masato but doesn't remember anything the original one did.
Maybe he's engaged to her, he seems terrified of her I doubt that if she pushed him a bit he'd say yes, either that or the incurable disease is his marriage and his in the hospital from some struggle they had.
I'm not a feet dude but I understood the anklet, especially the second one.
Also false advertising on the swimsuit page, we've all seen the "totally not Takamine-san OC" that the author uses for his hentai work, we know she's bushy down there.
So we know the girl at the end and the twintailed landmine are love eaters, the tomboy said she knew him from before, am I forgetting something or is there more information to know who the othe 2 love eaters are?