Sorry, my answer may not be clear enough. If you ask the manga author if he would draw sequels or derivative works of the same work, the answer is no. Most manga authors would set a clear storyline and ending for their works and would not draw sequels or derivative works. This was because comics were a commercial activity, and authors would usually obtain economic benefits through the sale of copyrights. Sequels or derivative works might violate the copyright of the original work, so they were not accepted by the author.
The 'obey me novel' often involves a story where the protagonist is immersed in a world full of demons. There are various characters with unique personalities and powers. The plot usually includes elements of the protagonist's interactions with these demons, building relationships, and dealing with different challenges and mysteries in this otherworldly setting.
In 'obey me novel', the main characters are the human protagonist and the group of demons. Among the demons, Mammon is known for his greed and his rather comical antics. Leviathan is the otaku - like demon who is into anime and games. There are also other brothers like Satan, Asmodeus, Beelzebub, and Belphegor, all with their own quirks and characteristics that play important roles in the story.