Maybe Joshu was onto something by dismissing Tooru as just the wind. If he doesn't think about him, he shouldn't go under a calamity, right? That was why Tooru broke off that branch for seemingly no reason, to make his presence known to Yasuho and Joshu.
Also I guess Joshu was fully willing to fuse into a whole nother person with Yasuho but totally chickened out when he realized he was gonna go through something a bit more painful lmao