Relic lived in a rich family, but her parents both died when their mansion was on fire, only little Relic who still had twintails and little Rob survived from the disaster.
Soon Rob found out it was a cruel crime family that burned their mansion and tried to caught them (maybe for the inheritance?), so they escaped to an apartment and hid from those chasers, and Rob changed Relic's twintails into hair knots for the disguise. Unfortunately, she still be caught by them and Rob secretly joined into one of them for saving Relic.
The family from the Red Mansion adopted Relic, and trained her to use weapons, but she refused to kill anyone. She was very afraid of the leader, and the leader didn't allow her to have any freedom including went out of their mansion. She didn't know that Rob who was retinue of the family was her brother because she hadn't seen him after she had been caught by the people of Red Mansion.
One day Relic wanted to go outside of the mansion, so she asked Rob to help her. Rob gave his black uniform to let Relic disguising into his outlook because they look a same. She started to ride her pony and explore the outside world without telling anyone except Rob.
Then she met a girl (Eek) who also from a crime family in Blue Mansion which was the enemy of the Red Mansion crime family. They became a friend and liked to talk about flowers.
After 10 times meeting to the girl, the family finally found that Relic had gone out of the mansion, they used the reason of it was the Blue Mansion family which hid Relic, and attacked the Blue Mansion. When Relic arrived to Blue Mansion, the girl and the people of Blue Mansion had all died.
Relic felt guilty for what happened to the Blue Mansion and hated the people of Red Mansion including Rob, so she locked herself in her room and kept dreaming to avoid the reality.
In ED1, Relic can't get over the guilty and the fear of the people from the Red Mansion, so she commits suicide.
In ED2, Relic wanted to revenge the death of Eek, then she killed Rob and became the cool blooded killer that the Red Mansion wanted.
In ED3, after talking to Rob in the dream (maybe they're twins and had some special connection between them), Relic finally knew all of the truth, so they decided to kill the head of the Red Mansion together, but failed.
In ED4, Relic had faced the fear in her lucid dream, but decided to escape, so when Relic and Rob met, they killed each other to escape from their life of sadness.
In ED5, Relic had faced the fear in her lucid dream, she conquered the fears successfully, so in the final they win the battle from the head of Red Mansion and gain the freedom.