Two Worlds

Serenity was a Mary Sue slain by Agents Jay and Acacia. She appeared in a Lord of the Rings/Harry Potter crossover.

Character history
Serenity was the "half-elf, half-witch" daughter of Galadriel and Remus Lupin. She was so beautiful that a spell had to be put on her to conceal her beauty. Ron Weasley was her boyfriend, though somehow she also managed to be friends with Draco Malfoy. She was an expert archer and swordswoman, and a Seeker on the Gryffindor Quidditch team. Serenity was traumatized when she found that Ron was dating Lavender as well as her. Then she fell in love with Legolas instead.

Character demise
Jay opened a portal and asked Serenity to step through it, which she did. The portal, of course, led to the Whomping Willow.

Mission Report
Two Worlds, Agents Jay and Acacia, Department of Implausible Crossovers