Multiple Personalities

Background

Multiple Personalities is the ability in which one has have several different personalities in one's mind. This ability has a number of advantages and a number of shortcomings. It also extends further from just having dissociative identity disorder, as one could have multiple souls, minds, or organisms within their body.

Variations

• Multiple Personalities: The most known variation, this one is gained from a disorder where one may feel as if they have two or more people talking or living inside their head, each identity normally having a unique name, personal history and features. While in most cases the user is suffering from an illness, rare cases in fiction it can be due to other reasons, such as someone manipulating the users mind.
  • User: Ami (Gwain Saga), Ice Man (Mega Man), Buzz Lightyear (Toy Story)

• Multiple Organisms: Another popular known variation, this is where the user has another organism within them, the most popular example being a parasite. Though it could also be an organism that possesses more then one brain or more then one head, allowing them to have multiple organisms within them.
  • User: Spider-Man with the Black Suit (Raimi Spider-Man Trilogy)

Alien X possesses 3 minds that control it, Ben, Bellicus, and Serena, with all three needing to agree in order to get a motion carried

• Multiple Minds: This one branches into more philosophical territory where one has multiple minds inside of them, effectively having multiple personalities. This is essentially the multiple personalities state without it being due to mental illness, but rather there actually being multiple minds living inside of the persons body.
  • User: Tanjiro Kamado (Demon Slayer)

"Whisper Sephiroth" is the Nexus Embodiment of the Whispers, thus having multiple souls within him

• Multiple Souls: One of the more rare cases, this one also branches into philosophy, where instead of having one soul, one has multiple souls co-existing inside of them. This is another case where they are in a state of multiple personalities without it being due to a mental illness.
  • User: Okeya Fuuta and Kouko Ishigami (Spirit Circle), Ichigo Kurosaki (Bleach)

Possible Uses

• The division of roles - Each personality can be strong in some ways and is only activated when there is a need for its services.
• Collective Intelligence - One head is good, two is better, and if one head has a million consciousness at once, with a sufficient level of organization, they can replace a strategic headquarters or scientific institute.
• Change in body - Switching between personalities may also change the body, getting different (and likely necessary) skills and abilities.
• Mental resistance - The presence of a large number of consciousness allows resistance to mental influences, because even if one of them succumbs to external control, the other personalities immediately bring the wayward personality to its senses.

Limitations

• Disorganization/chaos/power struggle - If each personality pulls control towards itself, a situation may arise in which control of the body randomly shifts from one mind to another, which obviously does not benefit the whole person.
• Increased complexity of control - Usually if there is one dominant personality, it has to constantly monitor all the other consciousness, which requires considerable effort, and in certain situations severely limits other abilities (because there is no mental direction at the other faculties of the body).
• Problems with memory - Because the personalities are still autonomous, when you switch from one to another, the memory information may be lost. Or else, one of the personalities may unknowingly erase the memories that are important to the another.