Michael

Michael (ミカエル) was the will that formerly resided within the Ultimate Skill Michael. He served a relatively lengthy role in the story as an antagonist, being the leader of the forces residing within heaven. He met his end in battle against Rimuru Tempest.

Appearance
Michael, who possessed the body of Rudra Nam Ul Nasca, had an identical appearance; the only exception were his eyes which are depicted as red in illustrations. He originally wore Rudra's full-body, black and gold outfit, but after the events of The Abyss Unleashed, he switched to a white outfit with red accents.

Personality
Michael was extremely self-righteous and believed that his way of thinking was supreme and embodied justice, befitting the virtue he represented. He was the very opposite of his host, Rudra, who believed that there was no such thing as "absolute justice" or justice that could be accepted by all intelligent life.

Following Obera's betrayal, Michael came to experience feelings such as anger for the first time, which he, in his long life, failed to understand as someone who relied on logical reasoning and calculations for his decisions. While cherishing this newfound experience, he came to believe that instead of getting worked up over every setback, it would be constructive to avoid making mistakes in the future. Michael did not like imposing his mistakes onto others, and instead preferred to set them straight to avoid causing friction in his future plans.

In his final moments, Michael admits that he already long suspected that Veldanava had abandoned him, but refusing to acknowledge it, he suppressed this suspicion in the back of his mind to the bitter end. He always felt that happiness was out of his reach, having failed to reproduce the feeling many times in the past, but as his life neared its end within Rimuru, he found himself re-experiencing this lost feeling which he long dismissed any hopes of feeling again after the loss of his master. He lived his final moments in happiness, with his only regret being leaving Feldway behind.

Background
Michael was originally a hollow ego that resided inside a skill, questioning its purpose for living after the death of its master, Veldanava. Seeking to revive him, it allied with Feldway who shared a similar goal. Finding it inconvenient that it didn't have a proper name, Feldway named it "Michael", and as a result, his ego left its skill housing and became a Manas, developing a much firmer will.

To enact their plan, Michael spent the next several centuries wresting control of Rudra's body, gradually succeeding the more the latter's soul wore out with each reincarnation. He placed the minds of Rudra's closest vassals, including his partner, Velgrynd, under his control. Upon Feldway's recommendation, Michael also formed a truce with the Insectars and their king, Zelanus, whom the Phantoms had long been in conflict with. Because of Rudra's incredible spiritual strength, Michael couldn't completely act freely and was forced to play along in his game with Guy Crimson to the very end.

At the climax of the war with Rimuru's forces, Rudra's soul was completely banished, erasing any fetters placed on Michael. He chose to retreat with Feldway, moving their base of operations to the Heavenly Star Palace.

Trivia

 * According to Feldway, Michael had a similar presence to Veldanava.