He lived in the modern world, but demons and magic became real one day. The only way to kill these things was to use a new concept called skills, and culture changed greatly. Even so, the world was destroyed more and more every day. When Riley was born in his previous world, he first held the holy sword at three years old. From then, he trained and trained to kill the enemy destroying the world. He did as he asked in his despair. He killed humans and demons. In exchange for saving one town, other people would die. When the people said they were better off without him, he left them alone, and they still died. No matter what he did, people blamed him. He died fighting the demon king, who treated him more respectfully than most of the humans he met.
Since the modern world turned into a post-Apocalyptic setting, the most emotional struggles he had were against humans themselves. Since everything went to Hell, crime and chaos became prominent. I believe he first kills a human when he is seven. His teacher raped his sister, so he eventually hunted down and killed his own teacher. His "best friend" actually plotted against him and murdered his parents, and he chose to chase and kill his best friend once he found out years later. The priestess he served cursed him to be unable to commit suicide. It sounds like a warped blessing until you learn that she was extremely corrupt and guilty of any number of crimes. By forcing him to live and obey her bidding, he witnessed and participated in atrocities under her command.
He truly saw the worst of humanity. As he died, his only goal was to rest in peace. When he was reborn against his will, his intention was to do anything to avoid living such a hateful life again. Like one of those reincarnated-into-a-villain series with MCs who try to avoid death flags, Riley does everything he can to avoid hero flags. He fulfilled his duties before, and he wants nothing more of it.
He becomes completely favored by the dragon king once he joins up with the dragons, too.
Hormones are secreted by glands. In that case, the easiest thing to do to prevent a person from becoming an omega would be to remove those glands and then supply the person with supplemental hormones to make up for what the body is lacking. Since it's sci-fi, there might not even be any scars left behind. Instead, these characters go through the trouble of using medication. Even then, the MC is not aware that he's supposed to be an omega, which is a significant failure of the mother. Kids often don't take their medications, even more so than adults. How are you going to convince someone to take a pill every day at the same time without fail without explaining what its purpose is? Even then, this medication is just something the so-called doctor brewed up on his own. It hasn't undergone any clinical trials and doesn't appear to have been monitored for side-effects or interactions with other things. For all we know, this medication could cause his hormonal or immune system to fail or make him develop cancer. Even then, no one informed this kid that he was a guinea pig.
The mother has failed in her duties to explain the true situation to her son. We know that she is "sickly" but don't know what from and don't know her true reasons for doing what she is doing. She has no character depth.
For some reason, they are allowed to have pets out and in the open. Did someone manage to cure allergies? It really doesn't make sense for this to be allowed. Pets are often not obedient. Even if they are, they could send someone into anaphylaxis by just being near them.
This "dog" then sneaks his way through a scanner while pretending to be part of a white sweater. Since when does a scanner care what color you are? As long as you have bones, you should definitely show up, even with our modern-day technology.
When the enemy general shows up and takes control of the MC's ship, no one dies. No one is killed off as an example. Then, the "good guy" General Rosen shows up and saves the day without losing a single soldier, completely making the scene lose any and all suspense. For the enemy general, he seriously wasted all his time and fuel to come up here and say hello. Isn't that a waste? Shouldn't he have at least predicted that his opponents would try to fight it out with him? Shouldn't he have at least put a high explosive on board just in case this situation occurred? Better yet, if negotiations failed, he could blow up the ship and then flee. If they didn't chase them, then he got to kill some of the enemy anyway. If they did chase him, then he could use that opportunity to lure them into an ambush. Instead of planning things out, he is immediately taken by surprise and skiddadles away like a startled spider without doing hardly anything at all. All he does is poke Rosen about his former crush and hurt his feelings a bit. He gets very smug about this, too. What the hell? Is this guy really a general? Was it really worth coming all this way just to annoy this guy? Wasting all the time, money, and soldiers doesn't make sense for such a simple hello.
Ling Yu abruptly goes into estrus. He's one of the few characters in this series so far who has demonstrated any sign of intelligence, so props to him. He actually anticipated that his medicine would fail and took some preventative measures. He had someone else command the battle for him and locked himself in an isolated cell. If it were handled a bit better, then no one would necessarily have to know he was an omega. Even though he isolates himself, Rosen goes out of his way to enter the cell and rape Ling Yu, taking extra care to mark and impregnate him against his will. Rosen claims he is doing this for Ling Yu's own good since he would otherwise be an omega in a prison. Even so, taking these risks and avoiding bonding with an alpha or doing any of this was what Ling Yu decided. Ling Yu preferred to go to prison and do his time rather than becoming a birthing machine, and this is entirely his choice to make. If Rosen had handled this properly and covered it up well from the beginning, all this would be unnecessary, and no one would know the wiser. Ling Yu could flee without going to prison or hiding his gender. Instead, Rosen took advantage of Ling Yu's time of weakness to essentially enslave Ling Yu to him, completely destroying all their years of trust and friendship. He treats Ling Yu as an object rather than a person. Did Rosen honestly expect Ling Yu to still like him after he violated him to such an extent?
Naturally, Ling Yu could trust him no longer and knocked Rosen out before fleeing and presumably faking his death, which is quite sensible. Rosen is broken-hearted? It wouldn't have turned out this way if he weren't a rapist. He deserves all the suffering.
During all of this, Rosen is completely neglecting his duties as a general and irresponsibly leaving it to others. Ling Yu already told you "no, " dude.
Anyway, Ling Yu was a tough person in the military and was fairly high-ranking. Yet, he got out of prison and put on house-arrest. In spite of all that, he escapes extremely easily. Do criminals in this world not even have ankle bracelets to track their position like the ones in our world on house arrest do? If you tamper with those things, they go off. Since this is a sci-fi world, I would expect these devices to be even more advanced and possibly located under the skin to monitor the convict's vitals and status of this pregnancy.