In a classical fantasy RPG envoirment a hero is going through the final dungeon to fight the End Boss. As it happens, the hero is male and the End Boss is female. The End Boss can't help but fall in love with the hero and that's how the story begins in both Superios and Maoyuu Maou Yuusha. In the first manga the End Boss is evil and joins the hero's side, in the second one the End Boss is actually not quite evil and the hero joins her side. If you liked one of those two manga, you should try reading the other one.
They are both extremely similar in the sense that the demon 'King' so to speak falls in love with the hero and goes on a journey together with them. This leads to interesting interactions between the human and demon side.
In a land overrun by yoma - monsters that feed upon human innards and take on the appearance and memories of their victims - humans are little more than cattle awaiting slaughter. The only opposition to the yoma is The Organization, a group led by a council of mysterious men who send out their all-female warriors (known as claymores) to do their bidding. However, The Organization is not charitable; a town must pay an exorbitant fee for their services. Likewise, many of the claymores care little for those who they protect. Clare, the lowest ranked claymore, lives only so that she may one day avenge her mentor.
I couldn't help but think of Claymore while reading Superior. Yeah it's pretty much gut feel. The only obvious similarity between them, is the fact that both of those are medieval fantasy manga (though I'm sure there are plenty not so obvious similarities). Nonetheless, if you liked one of those two manga then you should definitely give the other one a try.
Both manga feature a couple who used to be enemies at some point, but who ended up traveling together and growing feelings for each other. Both of those series are action adventure ones, so it's highly possible that you'll like one if you liked the other one.
Munsu is an Angyo Onshi - an arbiter for the country of Jushin. Fighting evil is all he knows, but since Jushin has recently collapsed, what is he fighting for? Wandering from place to place, Munsu finds himself battling those who would further destabilize the country, whether they be arms dealers, smugglers, tyrants, or necromancers. Accompanied by a female warrior named Chun Hyang and able to call upon the strength of a ghostly legion with his Angyo Onshi powers, Munsu sets out to help those who are willing to take a step towards helping themselves, and bring justice against all that is evil in the world.
Both the main characters in this manga's have only one goal, killing the person/demon who made them suffer (killing parents/losing the one they love/friends) Together with two "friends" they travel to complete their tasks. Although they think that they know everything it seems that a lot of secrets will be revealed about their relations with their sworn enemy. Also both manga's take place in a world where demons and human are enemies.
Superior has more humor and Shin Angyo Onshi has more gore and a more complicated story but both stories have the same plotline.
Both The Legend of Maian and Superior feature a female end-boss (you know like the ones in RPGs) as a female lead. Their common sense is that of a villain, but since they get to hang out with a good guy, they have to adjust their way of thinking "a bit". Both series are medieval-like, action-adventure series, so if you liked one, the other one should prove interesting too.