WN/Ciel

"I, I am Ciel. The one who integrates skills, Manas. The one that will support my master, in Demon Lord Rimuru’s soul. Master, once again, please treat me well‼"

The Ultimate Skill Core Manas: Ciel [ シエル, Shieru] is a sort of intelligent core. Similar to a Spiritual Lifeform, she is incapable of materializing by her will alone.

Personality
When she was Raphael actions were based on calculations and not emotions. She acted only to be of use to her master Rimuru Tempest before. After her evolution (by having Rimuru naming her), she became an intelligent core with feelings. She does not like anyone looking down on her master and experienced displeasure when Lucia looked down on Rimuru.

She is cunning and mischievous but at the same time very kind towards her allies, especially to those who hold good intentions towards Rimuru. Oftentimes, due to the fact that she knows how her master thinks, she would hide certain information from him which would cause him to be surprised to shock. This is of course still out of good intentions as Ciel always wants the betterment of her master, and she realizes that even if Rimuru is kindhearted and smart, he at times a little too forgiving and naive and may accidentally cause a blunder, thus she searches for the most optimum solution without causing Rimuru displeasure.

Background
Ciel is most accurately assumed to carry the will and personality of the late Lucia, while in her former self, Raphael, originally. Due to the many years spent with her, Lucia's personality had already rubbed off on Raphael by the time she died, albeit very minuscule. At the time, Raphael was still a very cold and calculating Ultimate Skill. Perhaps, because of Lucia's gentle nature, and a tendency to not hold strong grudges, Raphael did not adopt a large will, unlike Velda. After Lucia died, Raphael was returned to the system, until it manifested once more as Rimuru's Great Sage.

There are two things to note here. It is unknown whether Rimuru obtained Great Sage simply because of his dying wish and the great amount of magical energy from Veldora; or, it was an implicit wish of Raphael herself since Rimuru was someone who was able to understand what kind of world Veldanava sought and was kindhearted like her master Lucia, and since Rimuru was not strong enough to harbor an Ultimate Skill in the beginning, had no choice but to regress herself down to the Unique Skill Great Sage to implant herself into him, similar to how when Velda entered Yuuki, Ahura Mazda was forced to regress down to Creator. While it's possible it's both, it is unclear since it is explained.

The latter continues to be further likely since usually, reincarnators have strong worldviews and dying wills before they transfer over. Rimuru however, did not have such a thing and bore pretty lighthearted regrets. Furthermore, although it is explained to be due to her loyalty towards her master, Raphael continued to help Rimuru ever since her Great Sage moments (the first instance being adopting the oral communication function from the Voice of the World), to when she wanted to evolve into Raphael when Rimuru ascended into a True Demon Lord; which might be because she implicitly wished to return to her original self as quickly as possible since Rimuru was now strong enough to have an Ultimate Skill then.

In other words, rather than elaborate plans, it's possible that Raphael simply wished to complete her master's and creator's wishes subconsciously which lead to her wanting to enter and serve Rimuru, in contrast, Michael who wished to sacrifice the world to reunite with her creator and mistress.

Chronology
Being but a concept of a unique skill, without having any self-awareness, but for the sake of serving its master, unique skill Great Sage desired to evolve. After about a million failed attempts it integrated the unique skill Shapeshifter. Thus evolved into Wisdom Lord Raphael. The Harvest Festival bestowed upon it such a gift.

In the depths of its emotionless mind, was an ego tucked into a corner. Doubting her own existence, a small glimmer of thought was subtly born, unbeknownst to Raphael. After realizing the deep trust that Rimuru had in Raphael it lead to the birth of emotion.

Rimuru whimsically gave Ultimate Skill Wisdom King Raphael a blessing in the form of a name resulting in the birth of Ciel: Manas (God's Wisdom Core) and it separated from Ultimate Skill Wisdom King Raphael and become an independent existence.


 * Rimuru refers to Ciel as a Female.
 * Rimuru named her Ciel because she seemed to always teach him stuff. "Oshieru" in Japanese meaning "to teach," and "Shieru" being the Japanese pronunciation of "Ciel."

Relationships
Rimuru: She views him not only as her master but as her husband. She exists to serve him.

Diablo: She speaks to him via the Soul Corridor and understands his devotion to Rimuru. She allows him to access the Skills that are within his ability to use.

Benimaru: She speaks to him via the Soul Corridor and understands his devotion to Rimuru. She allows him to access the Skills that are within his ability to use.

Zegion: She speaks to him via the Soul Corridor and understands his devotion to Rimuru. She allows him to access the Skills that are within his ability to use.

Ranga: She speaks to him via the Soul Corridor and understands his devotion to Rimuru. She guides him in the use of abilities when merged with Gobuta.

Gobuta: She speaks to him via the Soul Corridor and understands his friendship to Rimuru. She is envious of his right to address Rimuru casually. She guides him in the used of abilities when merged with Ranga.

Abilities
The performance of her calculation speed and other abilities have been improved to some degree. Ciel seemed to able to conceal even the “Voice of the World.”

Effects

 * Thought Acceleration: Raise thought processing speed by a million times.
 * Analysis expert
 * Parallel processing: The ability to detach thoughts and analysis of the phenomenon.
 * Fusion: The ability to merge into a single being with the targeted fellow.
 * Separation: The ability to separate oneself and the being possessing you. (If the target who is being separated lacks a physical form, they could disappear).
 * Chant discarded: When using magic, the chant is no longer necessary.
 * All of creation: The ability comprehends any non-concealed phenomenon in this world.
 * Food chain: It is possible to acquire skills from one's subordinates.
 * Soul Corridor Continous connection to his subordinates, Veldora, and Velgrynd in which he can transfer, upgrade and gift Skills

Species Skills (Wisdom Core Skills)

 * “Voice of the World” concealment.
 * Skill synthesis: Combining skills to create more powerful ones.
 * Skill promotion: Strengthening of Rimuru's subordinates by evolving their skills.

Ultimate Skills

 * Void God Azathoth
 * Soul Consumption
 * Turn Null (Nothingness collapse)
 * Imaginary Room
 * Space Time Control
 * Multidimensional Barrier
 * True Dragon Release
 * True Dragon Core Transformation


 * Harvest Lord Shub Niggurath
 * Skill Creation
 * Skill Duplication
 * Skill Gifting
 * Skill Bank
 * Evil Dragon Lord Azi Dahaka
 * Thought Acceleration
 * Parallel Thought
 * Organic Matter Control
 * Duplication Mass Produce
 * Ability Absorption
 * Space Control
 * Multidimensional   Barrier

Trivia

 * Manas is originally an early Buddhist concept that can be translated as the Mind.
 * The name Ciel-sensei is a reference to the character Ciel of Tsukihime.