Nega Ciera

Because Negas are awesome
As Ciera is bubbly and unnaturally jubilant, Nega Ciera is her polar opposite; she's lean, mean, and green It's actually impossible to get her to smile. She's ALWAYS in a bad mood.

Since Ciera has spirit powers, I guess you can say Nega Ciera has shadow powers; an example would be that if Ciera can give life to a dying plant, Nega Ciera can sap the rest of the life out of it with Soul Absorption.

Egh, I'd hate to see how she'll be if she ate ramen... O_O She might be worse...