Definitely Lucius Malfoy. Since he is Draco's father, his influence on Draco could create internal conflict for Draco. If Lucius is against Draco saving Harry, it adds a whole new layer of drama. Bellatrix Lestrange is another good choice. Her insane and violent nature could pose a direct threat to Harry and make Draco and Blaose's task of saving him even more difficult. And don't forget Ginny. If Ginny has feelings for Harry and sees him getting closer to Draco or Blaose in a romantic way, it would cause a lot of jealousy and drama.
One character for extra drama could be Dumbledore. His mysterious ways and the secrets he might be keeping could impact the situation. If he has some knowledge about Harry's situation but doesn't share it fully with Draco and Blaose, it creates suspense. Then, the Weasley twins could be included. Their pranks and light - hearted nature could contrast with the serious situation of saving Harry, but also they could accidentally get in the way or reveal something important, causing more drama. And Pansy Parkinson, if she has a crush on Draco and is jealous of his growing relationship with Harry, she could stir up trouble.
Well, a plotline could be that Draco and Blaose are on a secret mission to save Harry from an unknown danger. They end up having to protect Harry in his own world, like at Hogwarts. Along the way, Harry realizes that Draco and Blaose are not as bad as he thought. And for the romance part, there could be a moment where Harry is injured and Draco or Blaose takes care of him tenderly, which sparks the romantic feelings. Maybe there's a ball at Hogwarts and Harry ends up dancing with one of them, much to everyone's surprise, and that's the start of their relationship.
Hermione would be a great addition. She could be the voice of reason and also use her vast knowledge of magic to help Harry and Draco in their high - stakes situation. For example, when they are facing a complex magical puzzle as part of their mission.
Well, in this kind of fanfiction, Draco and Blaise saving Harry and leading to a romance could be quite a wild ride. It might involve some magical adventure where they team up against a dark force. The change in their relationship with Harry could be gradual. At first, they might be reluctant allies, but as they face danger together, they start to understand each other on a deeper level. The romance could be a result of shared traumas and the realization that they have more in common than they thought, and it's a fresh take on the relationships within the Harry Potter universe.
Definitely Sirius Black. Since he was one of Lupin's best friends and also had a strong connection with Harry. His presence can add a lot of drama and backstory to the fanfiction.
Well, Hermione would be a great addition. She could use her intelligence to help Harry and Moka understand the different aspects of their two worlds. For example, she could research about yokai and find ways to use magic to help Moka control her vampire side better.
The Cullens from the Twilight series are obvious choices. They could interact with Harry in various ways. For example, Carlisle's medical knowledge and his calm, father - like presence could provide stability in a dangerous situation that Harry and Edward find themselves in.
Kaichou could be a great addition. Since she has a thing for Usui, her presence could create jealousy and drama. If she sees Usui getting closer to Yukimura, she might try to interfere. Another character could be a new transfer student who is really charming and tries to win over Yukimura, making Usui feel a bit possessive.
Obviously, Harry and Gabrielle themselves are essential. But characters like Hermione can add a lot too. She could be the one to help Gabrielle with her studies when she visits Hogwarts. Ron can also be there for some comic relief and to show the difference between the Hogwarts and Beauxbatons students.
Definitely Dumbledore. His wisdom would be crucial in guiding Harry and Maxima in any situation. Hermione would also be great as she could research and figure out how Maxima's powers work in relation to magic. And of course, Hagrid, who could introduce Maxima to the more unique and dangerous magical creatures in the wizarding world.
Neville Longbottom is a wonderful character to add. He has grown so much throughout the series and can be a great support to the trio. Dumbledore, even if in a ghost - like or memory form, can offer his great wisdom. Also, Draco Malfoy can be included in an interesting way. Maybe in fanfiction, he has a change of heart and teams up with the trio against a greater evil.