Keiki is not open enough with the MC. I ship them only bc they are fated otherwise I think he is too damn old for him, dubcon aside.
I liked Ayato right up to him attacking the MC, I was like wtf? Your best friend found out he was 1. Switched at birth, 2. An omega, 3. No longer a virgin bc keiki. His first response was not to console him but to blast some alpha pheromones to stimulate his heat and jump his ass while asking why can't it be me. There was nothing stopping him from confessing even while thinking riku was an alpha too but he didn't. He redeemed himself as a friend after apologizing and also following keiki's request to keep watching out for riku but he needs to stay over there in the friend zone.
You've got a point there. But then, maybe because it's ABO, alphas' behavior really isn't okay here. I mean, when Riku got into heat, was all confused and upset about what was going on, Keiki jumped him and was like "Admit that you are an omega." Like, dude... he believed for his whole life that he was an alpha, how can you be that...idk.
Then, he took his virginity when he was in that distressed state, plus he's underage. Keiki didn't show any consideration towards Riku who had a huge bomb dropped on him.
The way he came to his house to drop another bomb on him by saying he is not a child of people that raised him appeared to be a bit cold. I do excuse this by the fact that it had to be done, and that there probably wasn't a gentle way to deliver such news. Plus, Riku doesn't seem to be affected much (so far, I'm on 8th chapter now) by it or worried about relationship with his parents (his struggles are more focused on being omega), so I guess it's fine.
I definitely don't think that Ayato's behavior was okay, but I'm (kinda) excusing it with the fact that he is young (and maybe can't control his urges) and that alphas are territorial/possessive and led by instincts. Someone he loved lost virginity to another alpha, and he wanted to claim him. Kieki shows similar possessiveness few times though, so in that aspect, I can't really blame him either.
Like, both of them acted a bit forceful, lost control and failed to show some consideration for Riku. Kieki seems to be getting a bit gentler though. I don't dislike him, I just like Ayato a little bit more. But now I wouldn't necessary prefer him to be with Riku, I just hope he'll meet someone else and find his happiness too (a side story with him in focus would be great, but I feel like it's unlikely).

Am I the only one who prefers Ayato over Keiki? I'm only on chapter 5 tho. I thought it was super sweet how Ayato took care of Riku when they were kids and protected him. He loved him since they were kids, and seems to be really caring even now.
He did jump on Riku there, but at least he apologized later for doing that and hurting him. Keiki pretty much raped him (even though Riku was "feeling it", he was obviously in shock and confused by what was going on), then when Riku cried after that, he didn't apologize or comfort him. ://