It could be his mother, Narcissa Malfoy. She might be worried about Draco's change and try to figure out what's wrong with him. She could be in a state of shock seeing her once - proper son acting like a slob. Another character could be Harry Potter. Harry might initially be amused by Draco's transformation but then start to see it as a sign of something deeper going on with Draco and try to find out the real reason behind his slobbish behavior.
His father, Lucius Malfoy, might also be a main character. Lucius, who is always so concerned about appearances and family reputation, would be horrified by Draco's slobbishness. There could be a lot of conflict between them as Lucius tries to force Draco to be presentable again. And then there's Hermione Granger. Since she's always so neat and organized, she might be appalled by Draco's slobbish ways and get involved in some sort of rivalry or strange friendship with him because of it.
Another possibility is that a new original character could be the main character. This character could be a house - elf who is in charge of cleaning the bathrooms and has some interesting interactions with Draco while he's in the shower.
Another possible main character could be Snape. Given Snape's complex relationship with Draco in the original series, in this fanfiction, he could be either a mentor to Draco in his prodigious journey or have a more conflicted role as he tries to balance Draco's new status with the existing power structures in Hogwarts.
Hermione could be a main character. She might be the one who first suspects Draco's new role as the chosen one. Hermione's intelligence and inquisitive nature would lead her to notice the strange things happening around Draco. She could either be an ally or a skeptic, depending on how the story unfolds.
Hermione could be a main character. She might be the one who discovers Draco's situation and tries to help him out of pity or a sense of justice. Harry could also be involved, perhaps initially being suspicious of Draco's new state but then realizing it's not a trick.
Hermione could be a main character. Given her strong stance on equality, she might initially be suspicious of Draco but later come to understand his internal struggle as a half - blood. Their interactions could be filled with tension and, eventually, mutual understanding.
Harry Potter could be one of the main characters. Since he has a complex relationship with Draco, he might be intrigued by Draco's sleep - talking and try to use it to gain some understanding of Draco or even to tease him.
One possibility could be Harry Potter. Since they had a complex relationship during the war, Harry might play a role in either helping Draco clear his name or being one of those who initially believe the rumors about him. Another could be Hermione Granger. She's known for her intelligence and might be involved in uncovering the truth behind the false accusations against Draco.
Hermione is a very popular choice. Her intelligence and strong will can create interesting dynamics with Draco. Harry could also be included, as his rivalry with Draco is well - known. And then there's Ginny. Her fiery personality can add a lot of spice to the story when interacting with Draco.
Harry Potter would surely be one of the key characters. His relationship with Draco, which has always been a mix of rivalry and grudging respect, could play a huge role. As Draco switches sides, Harry would be initially suspicious but then come to accept and work with him. Hermione Granger is also likely to be important. Her intelligence and strong moral compass could influence Draco further and she could be the one to first recognize his change of heart.
I'm not sure specifically as there could be various interpretations. It might be a fan - made story where the character Draco is depicted in an unflattering way as a 'fat slob'. However, without reading the actual fanfiction, it's hard to say for certain.