Xerneas

Xerneas is the main antagonist in Yuki Kirigaya's Zetsubou-zen trilogy.

She appeared as the main antagonist of both Hope of Life and Jours de Démon and later the secondary antagonist in Discordiae Votum as her role within the second part was surpassed by the story's main villain.

Unlike her Official heroic counterpart, this version of Xerneas is totally evil and heartless.

Personality
This version of Xerneas is depicted as strongly evil, egotistical, cruel and devoted to her own goals above all else. She believes that the entire Terra World exists for her to lord over, and anything to the contrary can be annihilated. Xerneas is also megalomaniacal, power-hungry, delusional, embittered, heartless, and cynical.

Sometime ago, she was the personification of life and the one who brought peace on the Terra World, Xerneas was kind and pure of heart, but in a horrible turn of fate, her own power corrupted her with the awful actions of both Pokémon and humans.

Xerneas was, in the end, completely insane and never thoughtful of the lives of others: only herself, her pride, and her hatred towards the Terra World's existence that was not up to his standards.