Death of Karen Lilica is an event that took place 3 years prior to the beginning of the series.
Karen Lilica is a Blue Pegasus Celestial Spirit Mage widely known for her beauty and her multiple appearances in Sorcerer Magazine covers. Due to her widespread fame, Karen usually brings a group of men with her whenever returning to her guild. On one such occasion, Karen summons the Celestial Spirit Aries to entertain the men while she does something else. Seeing her actions, Master Bob scolds her for it, telling her that Celestial Spirits are living beings with feelings before warning her that she will suffer as well if she continues to do as she pleases.
Because of her being scolded, Karen later turns her anger out on Aries, beating her up and threatening to make her remain in the human world for a week. She then prepares to further punish her by chaining her up, but Aries is suddenly replaced by Karen's other spirit, Leo. Leo tells Karen to release him and Aries from her contract, telling her that she had lost her right to be their summoner and that other spirits are afraid that she might get their keys. Karen, however, refuses and tries to force close his gate. However, Leo refuses to return and says that he will remain in the human world until she releases them, making it impossible for Karen to summon other spirits due to the limitation of her Magic Power. Leo then leaves, telling her to visit him when she comes to her senses.
After about ten days, Karen visits Leo in the ruins near the town, asking him if he has yet to reach his limit. Leo, however, refuses to return unless she frees him and Aries. After a month, Karen returns to him, begging him to return and promising to never mistreat Aries again, but Leo thinks she's lying and refuses to listen to her. Karen becomes enraged and proceeds to beat Leo, but he stands firm with his decision and takes the beating.
Despite knowing that she will be unable to summon other Celestial Spirits because of Leo's rebellion, Karen decides to take a mission out of desperation. During the mission, however, she is killed by Angel of the Oración Seis who takes Aries' key.
Due to indirectly causing Karen's death, Leo is forced by the Celestial Spirit King to remain in the human world as punishment. While there, Leo takes the name of Loke and becomes a member of Fairy Tail. He later begins to date multiple girls at once, mimicking Karen's lifestyle, whilst carrying the guilt of her death. After three years, Loke begins to weaken and is about to die. However, he is pardoned by the Celestial Spirit King and, with Lucy's help, is allowed to return to the Celestial Spirit World as her spirit.
- Fairy Tail Manga: Chapter 72, Pages 14-15
- Fairy Tail Manga: Chapter 73, Pages 3-7
- Fairy Tail Manga: Chapter 73, Pages 8-14
- Fairy Tail Manga: Chapter 73, Pages 15-16
- Fairy Tail Manga: Chapter 73, Pages 16-17
- Fairy Tail Manga: Chapter 144, Page 3
- Fairy Tail Manga: Chapter 73, Page 2
- Fairy Tail Manga: Chapter 74, Pages 10-19