Kei Kusunoki

There was once an ogre (oni) mother who gave birth to human looking child. Instead of an ogre's horn, this child was born with a sword in hand called the "Onigirimaru" or Ogre Slayer. He has no name and is only refered to by the name of his sword. Though he appears human, he is pure ogre. Believing that he will become human once all of his kind vanished from the world of humans, he sets out on his destiny to slay all of his kind... (animenewsnetwork.com)

Housewife Nomi Yagami has such exceptional beauty that everyone nurtures romantic feelings towards her, including her own son.

A terrible war has ravaged the land, and now, fueled by the blood of numerous fallen warriors the Yōma, demons from hell, emerge once more. A skilled ninja seeks to end the bloodshed these demons inflict upon humanity, but to do this he must fight against his undead former best friend and fellow ninja who was killed in battle and has been resurrected to serve the Yōma. (Wikipedia)