Reiya Ohshima

Reiya is a young girl with blue-violet eyes, brown hair and a cute crush on young Loki. In the anime, she is the sole survivor of a rich family killed in a car accident, and she hires Loki to solve a mystery about her mansion. In the manga, she hires Loki because she has been having unsettling dreams about her deceased sister Lisa; she lives with her aunt, uncle, and two older cousins. Reiya's true identity is the transmigrated Norse goddess Freya—unlike Loki, however, Reiya's memory was wiped by Odin, so she has no memory of her past life.

Reiya becomes Freya when the necklace Brisingamen is put around her neck, but reverts back to Reiya when the necklace is removed, with no memory of what happens while wearing it. Freya, just like her alter ego, is enamoured with Loki, though she's far more aggressive about it than Reiya. Reiya is also capable of becoming Freya when extremely jealous or frightened, as well as other circumstances. Source: Wikipedia.