Menma Uzumaki (Chrono Nexus)

Menma is a being that should not exist- a living paradox. After Obito (in the disguise of Tobi) used Limited Tsukuyomi, his power touched upon an alternate reality. This other world paralleled the original ninja world, even down to its history and people, but with key differences. Unlike his counterpart, the Naruto of this dimension succumbed to the hatred and evil desires within him. Menma subsequently murdered and kidnapped other shinobi purely out of a desire to end their meaningless existences, and to enhance his own power.

After Obito's defeat and the cancellation of his Limited Tsukiyomi, Menma's evil should have been contained within his home dimension. Instead, the rogue ninja has ascertained a method of crossing the divides between worlds, and has wrought death and destruction beyond comprehension in pursuit of his ambition.

Menma Uzumaki is a criminal that goes beyond villages, beyond world-class calamities. His very presence in a dimension foretells its doom and descent into oblivion. He is the founder of the dimension-rending organization known as Unity and the inventor of the most malign of all forbidden techniques, the World Spiraling Key.