There are also fans who might be a bit nervous. They worry that the fanfiction they wrote might not be up to the standards that Dan and Phil expect. But overall, most fans are positive about it. They see it as a unique interaction between their idols and the fan - created content world. And this can lead to more fans being motivated to write better and more creative fanfiction in the hope that it might also be read by Dan and Phil.
Well, Serena would probably be over the moon. She's always been close to both Dan and Blair and would see this as a wonderful union. She'd be there for Blair during the pregnancy, helping her with shopping for baby clothes and giving her advice. Nate, on the other hand, would be more practical. He'd offer to help Dan with any financial or housing arrangements they need to make for the baby. And then there are the more catty friends, like Penelope and Hazel, who might be jealous and make snide remarks about how Dan and Blair got pregnant so quickly, but deep down they're just envious of their relationship.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
The Lord of the Mysteries is a Cthulu-style novel. The search results mentioned that 'Lord of the Mysteries' combined Cthulhu's style and elements of the system. Although some search results indicated that 'The Lord of the Mysteries' didn't emphasize the spicy flavor of grams, it could still be confirmed that the novel belonged to grams.