Niki is a former slave who was used to sell a certain drug in the streets of Lotto Valentino during the 1700s.

Spoiler

She ended up becoming friends Huey Laforet, Monica Campanella and Elmer C. Albatross in 1705, and in the ensuing years fell in love with Lebreau Fermet Viralesque. After suffering extensive injuries in 1711, she is given the Grand Panacea by Lucrezia de Dormentaire. The elixir preserves her wounds, and she spends the next three hundred years in constant agony—effectively breaking her mind.