- Awesome Music: "stone cold", the first opening theme.
- Ditto "Kiseki".
- Cliché Storm, or Troperiffic if you prefer.
- Complete Monster: Dr. Kenmi really shows his wickedness in later episodes. To activate the mysterious Darkstone powers, Kenmi enacted torturous experiments on people and had murdered one heroine, Ruri's, parents in order to force Ruri's sister Aoi to activate her powers. Kenmi later attempts to rip out another heroine's heart after causing her financial ruin for his experiments, and is even revealed to have been behind the "random" Darkstone attacks early in the series that had caused so much grief, all in an attempt to force his test subjects to go berserk.
- Ensemble Darkhorse: Kenmi's SP, despite her light amount of screen time. Most likely due to her unusual personality of lazing about with headphones on and doing nothing but eating and drinking until it comes time to fight, where she proves to actually be a very good combatant while still goofing around, making funny noises, and taunting while fighting, yet giving up when it gets boring. Naturally, she annoys serious people like Naito by showing up as he's trying to exact revenge on Kenmi.
*Come-get-me taunt while she wiggles the "ears" on her armor*Naito: "YOU THINK THIS IS A GAME!?"
- Magnificent Bastard: Kenmi in how he keeps himself out of suspicion even with evidence looking right into the protagonists faces.
- Moral Event Horizon: Kenmi crosses it if not for his inhuman experiments, it's for his murder of Ruri's parents and the crystalization of Aoi to get her to activate her powers. On Christmas no less.
- Narm: In episode 12, Fei turns into a Darkstone as he thinks Naito has died because of his uselessness. The fact that he wants to kill Kenmi is very dramatic. The fact that his Darkstone armor resembles a purple and green robot bear with ears that would make Mickey Mouse's jaw drop completely ruins the drama.
- Viewer Gender Confusion: Many, many viewers believed that Fei was a girl. Doesn't help that the fansubs refer to him as a "she".