Nightshroud

Nightshroud's powers and abilities

Nightshroud is a supernatural entity capable of possessing other individuals. He was capable of possessing both Atticus Rhodes and Yusuke Fujiwara. His means of possession however seem to differ from person to person. In Atticus' case, he was only capable of exerting his control through "Red-Eyes Darkness Dragon" and "Red-Eyes Darkness Metal Dragon" and once Atticus stopped using both cards it ceased any influence Nightshroud had over him. In Fujiwara's case it seemed to be in full control over him, mostly due to his negative feelings. Regardless defeating the possessed individual in a Duel will render the control null.

As seen with the aforementioned "Red-Eyes" monsters it is implied he is capable of upgrading monster cards. Even when possessing individuals Nightshroud is able to do so only through mere parts of him. This enables him to survive despite even losing a Shadow Game in which his soul is gambled.

Being the origin of the World of Darkness he has full control over the dimension, being able to direct and likely create the army of Trueman to assault the human world and imprison nearly all of the planet's inhabitants into his own world. Due to being born out of the darkness of human hearts, Nightshroud is essentially eternal and omnipresent and therefore can't be permanently defeated though he can be fended off.