"Good ev-evening, you had q-questions?" Quirrell greeted the two.

"Yes sir. I've heard many references to Dark and Light, and Chaos and Order magic, but the explanations are a little vague," Harry started.

"Yes, they tend t-to be. So do y-you want to know w-what magic is, or do you want the p-political explanation?"

Harry was confused, "What it is, I guess."

Quirrell lent back against his test, toying with the end of his turban idly. "Hmm, w-well then that is technically out of my teaching r-range, since Defence Against the D-Dark Arts is mostly against what is p-politically determined Dark, or rather, Bad. Dark and Light are the modern t-terms for Chaos and Order. Light is Order, and Dark; Ch-Chaos. Of course, these t-terms inspired the synonymous l-link to Good and Bad, but t-that is really just a technicality in the language and isn't r-reflected in the nature of the m-magic.

The main difference is that Order magic is drawn from w-within with caster. The intention is shaped with language, r-runes and wand movements, and arithmetic calculations. It is e-easier, more predictable and safer, so u-usually also exclusively taught in schools. Merlin was the first L-Light Lord, since he not only invented the s-staff and, by association, what we know as Light magic, but he was also r-ridiculously powerful.

Chaos magic is older, more… p-primal, less structured, I suppose you could say. To understand th-that there is Chaos magic, you must first c-comprehend how there is magical e-energy in all matter. This residual magic, a potential for g-great power, is only influenced by will and e-emotion to produce the effect, but most w-weak magicians can't actually do this. That's why we don't hear about m-many wizards or witches from ancient times; most, without w-wands, could only live as muggles, with the occasional a-accidental magic incident. Chaos magic is often overwhelming, practically alive, and that is what makes it dangerous. Morgana is famous for o-opposing Merlin, and she was the first Dark Lady, allegedly a-appointed by Magic itself to ensure the b-balance.

Since Merlin and Morgana, t-there have always been a Dark and Light L-Lord. Very little magic is exclusively Dark or Light, m-most are the shades of grey we affectionately call neutral. In B-Britain at least, there is very little true Dark Magic left in practice, with the e-exception of a few rituals and the Patronus Ch-Charm."

"Patronus?" Harry prompted when the Professor paused.

"It is a protective charm u-used to fend off d-dementors. It relies on happy emotion, and produces an a-animal guardian. It's also h-helpful and therefore politically good, but t-there you have it."

"What about the Unforgivables?" Draco asked. Even he was interested, and he knew most of the basics already.

"Light, Dark, N-Neutral. They require tightly controlled i-intent, which is present in both types of magic, but the necessary stimulus of emotion m-makes the Torture Curse mostly Dark, while the K-Killing is more neutral. The Imperious is s-strictly Light, since it takes and offers c-complete control. They were banned and all labelled as Dark."

If their names even alluded to their effect, Harry didn't have to wonder why they were considered nasty. "So the stigma is against nasty spells, not Dark magic itself? Why don't they teach us this in class?"

"C-can you guess who t-the Light Lord of this e-era is?"

"Dumbledore," Sasha spat. Harry had quite forgotten she was there, she was so oddly silent.

"D-Dumbledore has quite a political following and he g-gains more power for his side by l-limiting the Dark. He gained notoriety when defeated Grindleward, the Dark L-Lord, b-before Lord V-Vol-Voldemort, and most people listen to him."

Draco looked impressed that the Professor would be brave enough to even think that name.

"Before Dumbledore, t-the Light ruled in France for nearly a h-hundred years. T-the balance in E-Europe has been tipped, and i-it affects the world."

…

"Do you believe me now?" Harry asked as they left Quirrell's office, much, much later.

"Oh alright, he's not so useless." He sounded reluctant, but contrary to this, he was the one dragging Harry the next time either of them had a question.

"I don't trust him, he has an effective façade," Sasha insisted.

"I don't either, but really, where do you learn these words?"