It was a decent yaoi. I fail to see how it is original though. Well, the animal hierarchy idea offers something different but male pregnancy has actually become pretty common these days (at least in fantasy or supernatural stories). The couples are stereotypical (strong, silent seme vs weak and small uke, romeoxjuliet,foreign royalty and commoner, etc...) and so is their personalities. The society somewhat approves of multiple relationships but the characters are all monogamously minded so it didn't really work. Like...
Kunimasa had a girlfriend while he was pursuing Norio. He thought it'd be fine to have both but his girlfriend and Norio disagreed and made him pick one. Same goes for Seth, Salam, and Waka. Seth is Saudi Arabia royalty so it was okay for him to have many wives but Salam (first wife) hated the idea. He agreed because he wanted Seth happy but if he was really that against it, he should have just denied Seth's request. I don't even understand why they married. In the beginning, it was an arranged marriage to stabilize Seth's right to reign but when they meet two years later, the situation is still unstable. Seth said he loved Salam but if Waka was on his mind all the time, he really didn't. So really, Salam was useless
.
That said, I really did enjoy the secondary couples, minus the mermaid story. Good characters, diverse ways of getting together, and happy outcomes.The main couple was entertaining in the beginning but as the volumes increased, they became unremarkable. Especially when Norio is around Kunimasa's younger brother, who has the most annoying brother complex. I don't mind Norio's character alone but together, him and the younger brother start acting like kindergarten children. And not in the comedic way.
Overall, it's worth a try though. Just keep in mind that it's licensed and when you get to the last chapter, that's all you are gonna get unless you buy it.The scanlators are obeying the copyright law and will no longer release chapters.