Disclaimer is in chapter 1.
As classes got into full swing Xander began to question his choices when it came to electives, Ancient Runes and Arithmancy both tested his resolve to learn as much as he could about magic, and his interest in same. Until Arithmancy in particular, Xander didn't really think ANYTHING could make Magic boring.
Luckily, and unluckily as it were, he already had a base in Magical Number Theory. This was good in that he wasn't struggling in class, but he was even more bored than he would have been otherwise. Good and bad traveled as a pair, or so it seemed.
The base ideas in Magical Number Theory were fairly easy to grasp. Certain numbers held a power of their own. Three, Seven, and Eleven being the most common and powerful numbers most wizards encountered. It was magically beneficial to do things in a way that related to those numbers, such as brewing potions in batches of three doses, or being the Seventh Son of a Seventh Son.
For an even more pronounced effect you combined them, such as brewing eleven doses of a potion that required seven ingredients in three brewing steps. The real challenge, of course, wasn't in devising the most powerful way to make such a potion, but rather formulating a potion that did what you wanted while also requiring the arithmantic steps. Potions Masters had spent their entire lives carefully reformulating specific potions to take advantage of that common rule of magic.
Madame Vector had carefully introduced them to the Wave Graph of Magical Influence, which was basically what it sounded like a large graph that showed magical potency along one axis and numbers along the other.
"As you can see," She said, looking over the class, "Magical Potency increases as we approach the number three, then declines to its lowest ebb by the number five, only to increase again as we reach seven."
The class nodded, understanding that much from the clearly printed graph, but Hermione quickly raised her hand.
"Yes, Miss Granger?"
"What about Zero, Professor?" Hermione asked, frowning as she looked at the graph, "Your numbers start with one."
"Well you can hardly perform zero steps, or use zero ingredients in a potion, Miss Granger." Vector replied a little testily.
Hermione sank back, shrinking a little as several in the class laughed or sneered at her.
"The Number Zero is one of the most important mathematical concepts in history," Wednesday Addams spoke up softly, her voice still somehow being heard all through the room. "I find it difficult to believe that it has no bearing on Arithmancy."
"Yes, that doesn't mean it isn't so." Vector said calmly, looking around the class. "Scholars have studied magical numbers for thousands of years, since before Wizarding Society came to exist as we know it today. These are tested truths, and while they may not be complete they are as close as anyone has yet gotten. Should you be able to add to this knowledge, you will have truly made an impact on the world."
Silence followed that statement, and she nodded in satisfaction.
"Very well, take your quills and note this down..."
The quiet and peaceful school year didn't last long for Hogwarts, of course, since in short order Draco had managed to stir things up while in Care of Magical Creatures. He'd been injured by a Hippogriff and was milking that for all it was worth, promising retribution upon the animal and on Hagrid as the class Professor.
Now Xander didn't much know Hagrid, and he didn't have that class, but what he'd seen of the big guy had been good so he was having a hard time matching what Draco was saying with the man he'd met as a first year.
As it turned out there was a reason for that, which he learned in the Library was studying with Hermione and Wednesday.
"It was really all Draco's fault, you know," Hermione practically growled, her hands flipping pages with near violent motions. "Hagrid told him to be respectful, but he had to be... be..."
"Draco?" Xander asked mildly.
"Yes! Exactly!"
"Shhh!" Madame Pince hissed from behind her desk.
Hermione blushed and shrank down a little, "And I'll bet it's not even a bad injury..."
"It isn't." Xander said dryly, "Draco doesn't wear the sling in the dorms..."
"I knew it!" She hissed.
"That doesn't meant that Hagrid did right, though," Xander went on, "It's like you said, Draco was being Draco. If you're going to do something potentially dangerous, you have to know how people are going to act."
Hermione shrank down yet again, looking glum, "Well, when you put it that way."
Wednesday looked up, eyes narrowing as she pierced Hermione with a stare. "How do you know all the details?"
"I was there," Hermione said hotly. "I saw everything."
"That class was conducted at the same time as Ancient Runes, was it not?" Wednesday said quietly. "The class you attended with us?"
Hermione suddenly got nervous, "I, Um, well I'm not sure. Couldn't have been. Oh my, I have to go, I'll see you later!"
Wednesday and Xander exchanged glances as the girl ran out of the room.
"She's hiding something."
Xander smirked, "Ya think?"
The Addams scion merely rolled her eyes as his amused tone, "I fail to see how she could be in two classes at the same time."
"Don't know," Xander shrugged, "Magic?"
That earned him a glare, "Do NOT make me hurt you."
Then she paused, considered her words, and smiled slowly. "On second thought, please... make me hurt you."
Xander gulped at her tone, and it was his turn to squirm in his seat as he made a show of looking at his bare wrist. "Hey, look at the time. Gotta go."
Wednesday watched him bolt from the library and shook her head slightly as she smiled. He was such a fool, but not in a bad way she decided. Much like Uncle Fester, perhaps. On the surface Xander resembled her father, but Gomez Addams had a terrifying dark side beneath the clown's facade.
She had seen it once, when she was very young, and it still gave her shivers to this day. Of course, all Addams had their demons, but there was something truly exciting about the true unleashed darkness she'd witnessed that day.
Wednesday shook herself free of her reverie a moment later, carefully returning to her studies with disciplined intent.
Like her father, she too had a dark side. She merely chose to leash it in a different way.
Defense Against the Dark Arts started off with a bang, literally, when the professor used an incantation that sounded suspiciously like a child's mumbling, or perhaps an African city, to fire a piece of chewed bubblegum straight up Peeve's nose when the Poltergeist tried to prevent them from entering class.
This was the first time Xander had a chance to examine the Professor closely since the opening feast. On the surface there was nothing impressive to relate about the man, other than his old and frayed robes as Malfoy constantly pointed out. He seemed competent as a teacher, though, so Xander was relieved to not be dealing with another Lockhart.
Their first class brought about a new spell, and the introduction of the class to a creature known as a Boggart. Lupin brought them up to a Staff room and, after some words from Snape, selected Neville to be the first to try the new spell.
The spell, simply incanted as 'Riddikulas' was, on the surface, nothing but a joke spell. Make fun of someone by casting a simple cantrip to make them look stupid, which made Xander wonder why he hadn't heard of it already until he looked the spell up later and found that it was, pardon the pun, ridiculously easy to stop. Like most cantrips, it actually didn't work properly, if at all, against an unwilling Wizard.
Against the Boggart, however, it worked fine as Neville proved when he turned the image of Professor Snape into a crossdresser. Even many Slytherins laughed at that, including Xander, though he did keep it a little muffled.
After that the class was treated to a spin of the Wheel of Phobias as Lupin directed them in to face their Boggart and cast the cantrip to repel it.
After Seamus had given his Banshee laryngitis Lupin called out, "Harris!"
Xander moved forward, wand in hand, and blanched slightly as the boggart became two forms that lunged in his direction. A Black clad jack booted Gestapo glared at him, drawing a Luger, while a gaily colored clown with creepy face paint grinned at him wildly.
"R... Riddikulas!" Xander snapped, flicking his wand at the duo.
The two merged and in the next instant there was a Gestapo Clown wielding a floppy rubber chicken in a way that could no longer be remotely considered menacing.
"Excellent, back now," Lupin said, nodding to Wednesday. "Addams."
Wednesday calmly stepped forward and the Boggart changed instantly, looking suspiciously to Xander like Mary Poppins. The incantation rang out and Wednesday stepped back as the Boggart became one of the most hideous hags he'd ever imagined, cackling wildly while singing Supercalifragilisticexpialidocious. Xander, alone the entire room, burst out laughing wildly as everyone else screamed at the change.
Lupin, sparing puzzled glance at Wednesday, stepped in and calmly dispatched the Boggart when it turned into an image of the Moon for him. He moved away, then quickly nodded to Neville again, "Forward Neville! Finish him off!"
Neville did just that, considerably more confident this time as the crossdressing Snape made its reappearance once more.