Yondaime Ooyamato Tatsuyuki
Please be advised there is depiction and reference to child abuse, so if you are not comfortable with these themes I would not recommend this manga. The story is very well written, and thought out thoroughly. The heavier topics are handled in a mature way, giving them adequate attention. The art is a+ which is another bonus. I would strongly recommend reading this if you like happy endings, some very cute fluffy moments (mostly at the end and extra), and proactive bottoms.
Futari no Maharaja
There is explicit rape in this manga, be advised. I'm probably in the very small minority in saying that the only good thing about this is the art. I rarely get so annoyed about these sorts of story, but the little things culminated into one of the worst reading experiences ever. There wasn't a single character I liked. All that being said, if you enjoy stories about people being caught in another country, and intricate family dynamics you might find something in this that I could not.
Kirei na Onii-san ni Horeraremashita.
Warning: Dubious Consent The art is undeniably well done and for the most part the initial dynamic is enjoyable. It is revealed later on that one of the characters is must more promiscuous than initially hinted at. There is dubious consent near the end, which is up to you as a reader to decide if you're comfortable with it. On a whole it is one of the more mild moments considering the genre, but it's worth noting its presence.
Yoru To Asa No Uta