Queen of Darkness - preview

I've collected my copy last weekend, and I've started playing... so I thought I'd post the story preview and characters profile. Software translation of the story preview from the official website is rather garbled, so I'll try to write my own and hope I don't spoil it for anyone.

Story:

As the youngest princess of the royal family in the demon world, Risty also had the right to ascend to the throne like her older brothers even though she's not related to the king or her brothers by blood. That is, until it was announced that her eldest brother, Garum, was the one chosen to be the next demon king. Garum had betrayed Risty before, and he's the only person she truly hated... and if he became king, there was no telling what sort of treatment Risty would have to bear. With that in mind, Risty left the demon world for good, and went to the human world to establish her own place... to be a demon king in her own right.

Characters (in the same order as in the official site):

• Risty: The youngest princess of the demon kingdom. Headstrong, although sadly she doesn't really think far ahead regarding her actions. Often does questionable things because "it's interesting" (like letting her would-be assassin to live). Dislikes having others touching what is hers. When she became a ruler, that extends to her subjects; she dislikes other countries trying to destroy what's hers.
  
• Reiza: The second prince of the demon kingdom, Risty's older brother. He adores Risty... probably a bit too much. When Risty decided to leave the demon world, Reiza didn't even think twice to follow her. He threw away the magic mark that signified his right as one of the heir to the throne; a crime to which the punishment is death. Always smiling, although no one can really tell what's on his mind. He's quite the tactician, and helps Risty to manage her country's affairs.
  
• Hellvady: A half-demon, half-human whom Risty met upon her arrival in the human world when his village was under attack by Armaenan. As demons need to establish a contract with an inhabitant of the human world in order to live in it,Risty gave Hellvady an offer. If he would make a contract with her and swear his loyalty to her, she'd save his village. Hellvady agreed to the offer, and afterwards he became Risty's most loyal retainer and general. He's always serious and doesn't talk much, but he's also straightforward in telling others what he thinks. But it seems like he's hiding something from Risty...
• Cristval: A famed hero (and prince) from Armaenan who was sent as part of an army to defeat Risty. However his army was defeated instead and he was captured. Deciding that he'd be "fun to play with", Risty didn't kill him and even let him live in the castle, telling him to try to assassinate her whenever he wanted. A very religious and righteous person with a high moral standing, he found it difficult to understand demons' way of thinking.
• Garum: The first prince of the demon kingdom, Garum does what he wants as he pleases (similar like Risty in that regards). He's loud and his manners is unrefined, but he's honest in that way. His relationship with Risty is shaky at best, with Risty detesting him and Garum not seeming to care about Risty's feeling. However, he doesn't seem to mind the fact that Risty moved to the human world to escape him; on the contrary he seems to support it...
  
• Meil: Hellvady's younger sister, who despite her look is at least 200 years old. Really loves her brother and tries to help him anyway she can. She also admires Risty (somewhat excessively), and always calls Risty "Onee-sama".