Michael

Michael is a high-ranking archangel in the Celestial Realm. He has not yet appeared in-game, but has been mentioned by other characters including Luke, who has stated that he "reports to Michael directly."

Appearance
Though Michael's appearance is not yet known, according to Satan, Michael's appearance is the complete opposite of Lucifer's. Luke also claims in Issue 6 of the RAD Newspaper that Michael has good fashion taste, particularly with accessories.

Personality
According to Lucifer in the chat Simeon's Complaint, Michael is "too upfront about his desires", causing him to place unreasonable responsibility onto those working under him. Despite the overworking and unreasonable demands, his subordinates seem to respect him greatly and view him as a good person.

Michael has an immense sweet tooth, and he's most often mentioned in relation to his desire for sweets. He has rather lavish and specific tastes, and is very eager to try Devildom sweets. Despite seeming to have a rather large appetite, he has no issue sparing food for others, having once sent Simeon and Luke a package of Celestial Realm confections while they were in the Devildom.

In 50-10, Michael is said to be interested in astronomy, having taught Luke and Mammon about human world constellations. This is later alluded to by Lucifer, who explains in lesson 52-7 that Michael had Raphael create a planetarium so he could view human world stars from the Celestial Realm.

According to Mammon in lesson 50-10, Michael is "weird".

In his one and currently only M|chat with Simeon, it is shown that Michael is calm yet stern when he is angry. He prefers to talk rather than use physical discipline, in contrast with Lucifer. The Devilgram A Job From Michael further exemplifies this approach, as he suggests to Lucifer using more gentle tactics to correct his brothers' behavior.

Story
Note: this section may include spoilers

Background
In Lesson 23-5, Barbatos mentions that Michael is the current leader of the Celestial Realm's legion of angels as well as the guardian angel of confectioners.

In Lesson 27-19, it is revealed by Asmo that Micheal used to teach Mammon, but didn't know how to deal with him. This led to Lucifer taking over.

When Lucifer was still an angel, the two appeared to have a friendly sibling rivalry. The two would do things to mildly annoy each other, such as Lucifer making sure to attend the opening of the first planetarium in the Celestial Realm in 52-7 because he knew Michael had wanted to be there first. They also had a habit of pushing their responsibilities onto each other, with Lucifer referring a lost MC to Michael and Michael making Lucifer go to a diplomatic meeting in Devildom in his place, which Lucifer gripes about in 44-15. However, the two have become estranged since the fallout of the Great Celestial War. They do not seem to have much contact with each other, and Lucifer's present-day feelings about Michael have not yet been explored.

Main Story
According to Luke in Lesson 5-12, Michael loves sweets of all kinds.

In Lesson 49, Luke commented that he often found Michael in the great hall of the Celestial Palace where portraits of Lucifer and his brothers used to hang when they were angels. He would simply stare at the empty space, lost in thought. He claims that, although he never says anything, Michael misses the demon brothers dearly and regrets both the Great Celestial War and their resulting departure from the Celestial Realm.

Relationships
Note: this section may include spoilers

Main Character
MC was supposed to meet with Michael at two points in the series, but has not yet done so. According to Luke before the first missed meeting, Michael had been greatly looking forward to meeting MC. Despite never officially meeting, it appears that Michael knows MC on some level. Raphael mentions in his character introduction video that he has heard a lot about MC from Michael.

The two may or may not have met when the Ring of Light was given to MC and MC communicated with an unknown person.

Lucifer
In Lesson 23-3, the brothers reveal that Michael had always admired and loved Lucifer. Michael and Lucifer once had a close brotherly relationship back when Lucifer was an angel. They were described as being "like twins", and Mammon stated that the two were very similar to each other. Towards the end of Season 3, it is revealed that Michael has collected very important mementos from Lucifer's time in the Celestial Realm. He was very quick to discover when one of these keepsakes — the Ring of Light — was stolen, implying he still keeps track of these keepsakes closely after all these years.

Mammon
Mammon formerly worked under Michael when he was still an angel, but Michael found it too difficult to deal with Mammon's troublemaking behavior and gave him to Lucifer to handle. Before this happened, Michael attempted to teach Mammon about the constellations, though Mammon apparently didn't absorb that information. This was mentioned in lesson 50-10. In the same scene, Mammon refers to Michael as "weird", saying he "could never forget someone as weird as him."

Luke
Luke reports directly to Michael, despite a massive gap between the two's ranks. This is because, though Luke is the lowest rank of angel, Michael sees a lot of potential in Luke and the power of his protective blessings, and has taken Luke under his wing. Because Michael has such strong faith in Luke, Luke has grown extremely attached to Michael, even to the point of idolizing him. He becomes extremely upset when others talk badly about Michael and always keeps Michael's interests in mind. He told MC in Lesson 5-12 that he wanted to work on his baking skills so that he could present him with a cake.

Simeon
Simeon, like Luke, also works under Michael. Simeon does not idolize Michael in the way Luke does, but seems to respect him. Michael often asks Simeon to run errands for Devildom sweets. In the midst of one such request, Simeon vents to Lucifer in the chat Simeon's Complaint. However, when Lucifer remarked that it must be a nightmare to work under Michael due to his demands, Simeon replied that he's not a bad angel.

Simeon seems to view Michael as a friend rather than just a superior; if MC points out that Simeon talks about Michael as though he were a regular angel in 23-7, Simeon explains that this is because they have known each other for a long time.

Raphael
Raphael also works under Michael, attending his needs closely. It is stated in his character introduction video that Raphael greatly respects Michael.

According to Belphegor in 56-1, a large part of Raphael's sour attitude that the other brothers have complained about is due to the stress of attending Michael's needs, which tend to be difficult to fulfill with very little reward.

Diavolo
The extent of Diavolo and Michael's relations are unknown, but it is implied they have interacted as Michael was directly involved in choosing students for the exchange program. Michael was also indicated to be frustrated with Diavolo for the secrets he kept in Season 2, using Simeon as a messenger in 31-16 Hard Mode to express to Diavolo that, if it's discovered that these secrets could affect the Celestial Realm, he will not hesitate to intervene.