AN: I've been writing chapter in a notebook at work as my code compiles. Hence, I have several chapters written but not typed or uploaded. Also, after reading some comments, I feel obligated to give an overall explanation. I don't know if I mentioned this in previous author's notes, but I never made it though all of Harry Potter. I read though the 5th book, but no further. What I did read, I read more than 4 years ago. This is not an excuse, but an explanation for the characters being the early, less likable, versions of themselves.
Trelawney screamed, which in and of itself was not particularly surprising. She typically reserved her most disruptive antics for inside the classroom, but the students supposed that the dinner feast could also be a reasonable time for her to decide to have a vision. She did seem fond of practicing her "gifts" where people could see her.
Harry watched detachedly. According to divinations, he'd been doomed from the very start. Another damning prophecy could hardly doom him more. He started to open his mouth to comment on this to Ron and Hermione but quickly snapped his jaw back shut when the air around Trelawney started to visibly warp and twist. This was clearly not her usual attention seeking. Even Hermione was caught off guard, all thoughts of exasperation immediately evaporated into concern.
The other teachers looked horrified. This thing, for it was very apparently not their comrade, thankfully seemed to take no interest in the students. It turned to face down the line of teachers at the table it was sitting at. The glowing yellow eyes locked onto Alucard, who calmly turned to meet its steady gaze. Professor Alucard simply raised an eyebrow and shook his head slightly. The thing nodded, made a shallow bowing motion, and Professor Trelawney returned to herself, looking confused and blinking owlishly.
The entire hall breathed a sigh of relief, dumbfounded and unnerved in equal parts at how easily the Defense Against the Dark Arts professor handled the situation.
Seras looked to Alucard, confused at the sudden turn of events, "What was that, Master?" She obliviously broke the humans' tense silence. All eyes were fixed on Alucard, all wanting the same answer.
Alucard hummed, "That was Marius," was the blunt, and underwhelming response.
"Will...Marius return?" Seras asked, now slightly concerned on behalf of the divinations professor, who still looked a little dazed.
Alucard thought for a moment before answering, "Hmm, probably. But he won't posses anyone else."
Dumbledore's eyes sparkled, "You seem quite confident in that statement." There was clearly more to their vampiric professor than even he had originally thought. "How can you be so confident that Marius won't possess anyone else?" The name felt awkward on his tongue. A possessing spirit that hadn't really interacted with anyone was difficult to envision as possessing anything as human as a name.
"Because I told him not to," was the blunt answer, "he prefers his own body anyway."
Dumbledore still looked like he wanted to continue the line of questioning, but allowed Alucard to leave stand and walk out of the main hall. Questioning eyes followed him as he exited, losing track of him as he turned around the first corner.
After recovering herself from the shock and revulsion, Umbridge stormed off in pursuit.
McGonagall looked at Dumbledore accusingly as the toad disappeared around the same corner that Alucard had just rounded mere seconds ago. "Are you absolutely sure that he's safe?" Already dubious of the vampire, this new revelation had her very wary. Her expression hardened, "Demonic possession is not something to be trifled with."
Dumbledore looked far to pleased with the situation than he should have been, "Aren't you curious how Alucard is not only acquainted with a demon powerful and intelligent enough to completely bypass Hogwarts security without setting off any alarms, but has enough control over it to have it unquestioningly obey even vague gestures?"
McGonagall looked as if she'd been slapped, "Are you not at all upset, or worried, that a monster like that managed to trespass on school grounds and possess a professor?"
Trelawney deemed that a good time to interrupt, "What are you talking about? There is no chance of a demon being able to enter Hogwarts."
"I'm glad to see that you are all right," Dumbledore said, "I will certainly speak to Alucard on the matter. Though, as it stands, it appears as if no harm was done. I'm inclined to trust his judgment since very little is known about half-demons and he seems well acquainted with this Marius figure."
"I suppose we really have no choice but to withhold judgment at this time since we have so little information," Snape drawled. "Why do you think it was a half-demon? Their very existence is questionable since nobody has ever actually seen one."
"Because the enchantments of Hogwarts are very sensitive to the infernal gates. Had they opened, the castle would have noticed the increase in energy. That would trigger not only alarms, but also an immediate lockdown of the entire premises. That creature didn't pass though the infernal gates to arrive here. Demons are drawn too strongly to Hell's dark power to be without for more than a few days. Marius must not have any such anchor since Hogwarts never detected a breach of the infernal gates." Dumbledore answered happily.
"Indeed, we were quite fortunate that hell's gates didn't spawn in the middle of dinner," Snape bit out caustically.
"Quite," Dumbledore chucked, willfully ignoring the slight. The rest of the professors looked concerned for his sanity.
Umbridge was fuming. How dare that infuriating half-breed simply walk away after something like that? She just had to prove his involvement and link him to foul play and he would be removed immediately. Maybe if she accused him of summoning that thing...maybe...She finally caught up with him. He walks too fast, she thought hatefully while trying to calm her panting. She'd had to run to catch up.
"How dare you," Umbridge panted as she slowed to a jog, "how dare you summon a demon in the middle of dinner?" She paused to catch her breath and noticed that he wasn't even bothering to show down. 'Infuriating creature,' she thought as she began to run to catch up again. "And then you just up and leave without answering anyone's questions." She glared at his back hoping to bore holes, but having no such luck. "I'll have you fired for this," she declared harshly. She paused, then continued to jog as he didn't even break his stride.
Alucard glanced over his shoulder, and then faced forward again, speaking as if to a petulant child, "First, I didn't summon Marius, he came of his own accord. Second, he's not a demon. Third, if you had a way to 'have me fired' you would have done so already."
She opened her mouth to continue her rant as Alucard dropped though the floor. She screamed in frustration and stormed to her atrociously pink office to stew.
The great hall heard a faint echo of her frustration and couldn't help but wonder at Alucard's uncanny ability to both navigate and completely ignore politics. Even the other professors were beginning to feel the effects of Umbridge's tyrannical reign as High Inquisitor. Only Alucard seemed entirely immune to any of her efforts. The teachers were briefly jealous, but also hopeful that Alucard would hinder Umbridge's inquisition.