Harry looked around his classroom proudly, having just finished improving it. Unlike his workshop, he hadn't gone overboard, mainly due to the fact he had decided to keep his mithril a secret. Other than Luna, none of his group had been explicitly told about his mithril, even if Ron had seen him create his mithril within the Chamber of Secrets.

Their group had changed since the end of the last year; Colin had already told him he would be skipping most of their sessions to spend more time with his brother, while Justin preferred studying with his Ravenclaw friends. Despite that, with Malfoy and Crabbe having said they would be joining their group their numbers hadn't changed.

The room now featured a large duelling ring in the centre of the room, which was a simple wooden circle hiding a mithril core. The circle was large enough that there was barely four feet between the walls of the classroom and the edge of the ring in some places, making movement within the classroom difficult if a duel was in progress.

A more permanent version of Tonks' duelling ward stopped any spells leaving the ring, along with a vertical version of the ward also protected the ceiling and floor. This left a green cylindrical shimmer of magic, barely visible until a spell crashed against it and the surrounding area lit up in response.

Outside the ring, there were a few desks arranged in a semicircle; which Luna sat upon, kicking her feet back and forth as she sketched into a notebook. Soon Neville and Ron entered, Ron ranting about their homework.

"Five feet on how to turn a hedgehog into a pincushion! Why do we even need to learn that?"

"It's more about getting you used to changing animals into objects, rather than specifically just a pincushion. Mainly so you can easily do the reverse, such as turning a letter into a bird." Harry explained.

"Yeah, well its stupid. It's going to take me forever to get five feet written and McGonagall gets prissy if I try and fill the space by writing bigger than normal."

"You should've started writing in large text from the beginning like I did Weasley, then she wouldn't have anything to complain about." Draco boasted, having just crept into the room followed by a bemused Crabbe and somebody under a notice-not. Forcing himself to see through that admittedly weak notice-not, Harry recognised Daphne's turquoise magic.

"Malfoy, didn't think you were going to show up." Neville greeted cordially, having glared Ron into silence before the redhead had a chance to make a retaliatory comment.

"Draco, Vincent… Daphne." Harry greeted, nodding to both the boys before fixing his gaze on Daphne's position against the wall.

"Daphne?" Crabbe asked, looking around as if expecting to see her sitting in one of the desks.

To Harry's dismay, Daphne refused to drop the spell, making him look mad instead of cool.

"Yeah, Harry… There's no one named Daphne here." Ron agreed, talking slowly as if Harry was an idiot.

Sighing, Harry summoned his wand into his hand and shot a finite at Daphne, which hit her just before she was able dodge out of the way.

"Spying now, Greengrass? I supposed it was you who was following us from transfiguration?" Draco asked affably, seemingly unbothered by her sudden reveal.

Huffing, Daphne smoothed her ruffled robes as she spoke, "I wasn't spying, I was… observing. I saw you follow after Weasley and Longbottom and was curious, then I heard Potter and figured you were conspiring or something."

"So, spying?" Luna clarified airily, earning her own glare from Daphne.

Instead of replying, Daphne turned to Draco and asked "How did you know I was there anyway?"

"You forgot to silence your feet, I heard you walking behind us." Draco explained. "I knew our stalker must've been from our class and you're probably the only student other than Potter in our year who can successfully cast a disillusionment charm."

"It was a notice-not actually, my disillusionment charm doesn't work properly yet." Daphne replied moodily.

"Oh? What happens when you cast it?" Harry asked curiously.

"Never you mind." Daphne said hastily, blushing lightly. "Anyway, how did you know I was there, because I am sure I didn't make a noise."

Before Harry could decide how he was going to answer, Draco solved the problem for him.

"He can see magic." He replied smugly, causing Daphne to at first roll her eyes in annoyance before looking around and realising he wasn't lying.

"Well shit, how did you get that skill? I assume that's part of your 'secret'?" She asked, sounding genuinely impressed, which caused Harry to subconsciously puff up with pride.

"Actually, no. I taught myself how to do it as a child, although admittedly I don't think my sight would be as strong if I didn't discover my secret. But, that doesn't explain how you know, Draco. As far as I'm aware only my teachers, Dumbledore and Luna know about my sight."

"Well it's obvious isn't it? I've seen your eyes follow spells that were basically invisible and whenever you do charms or transfiguration you always look like you are seeing something nobody else can." Seeing their surprised looks, Draco cockily added "Yeah, that's right, I can be observant when I want to be."

"We're just surprised, you often don't show the capacity." Harry explained, earning an indignant yell from the blond while everyone else nodded knowingly. "Anyway, you'll be pleased - Or perhaps disappointed- to learn that we aren't conspiring here, we're just studying." Harry explained to Daphne, who looked unimpressed.

"I didn't realise you all got on well enough to study together."

"Yeah well, events over the summer hammered home it's useless to hold a petty grudge against Potter, especially when it's so beneficial to be on his good side. If that means playing nice with his friends then that's a sacrifice I'm willing to bear." Draco explained.

"So what are you all studying? Because it doesn't sound like you'll here for Potter's wealth of knowledge for History or Astrology, you'd go to Zabini for that. Longbottom could explain Herbology but you just said having him and Weasley here is a sacrifice, not the reason you are here. I know you don't need the help in potions or charms, even if you aren't at my level. While Potter's good at transfiguration I highly doubt you'd be going to him for help given you are more than competent, meaning you're here for defence?"

"What about care? I could be getting help for that." Draco argued.

"Potter doesn't take care, he has runes with me" Daphne pointed out logically. "I guess you could be here for help with divination, but that doesn't seem like a subject you are particularly interested in, even then why bother going to Potter for help when both myself and Tracey are in your House."

"Fine, yes I'm here to learn from Potter how to defend myself better. Happy?"

"Immensely."

"Now that that's over with, do you think we can get on with it before dinner time?"

"Can I join?" Daphne asked innocently. "I could do with improving my defence grades."

Looking around and seeing none of his friends disagreeing, Harry agreed. "Sure. Now, before we begin learning anything I need to know how good you all are. So, I'll be duelling you all to get a feel for where you are strong and where you are weak."

"Sure, who're you going to duel first?" Ron asked, stuffing his recently finished homework into his bag.

"Oh I'm not going to fight you one on one, that would take way too long. I'm going to have all of you fight me at once." Harry replied, unable to hide his grin.

"This will be fun!" Daphne said, stepping forward eagerly. Draco, Neville and Ron looked less sure, while Luna looked like she was already planning the other girl's funeral.

Once they all got onto the duelling platform, Harry made sure to keep his back to the shield while maintaining enough space to dodge freely.

"Now, if you get turned green, then you're dead and should leave the ring. Otherwise, you should keep fighting. For instance, if one of you gets stunned, you are allowed to revive them. However, if you can get me in a state where I cannot fight any longer then you've won."

Getting nods from all of them, Harry began the duel. The main reason he wanted to fight all six of them at once was to give him the opportunity to properly test both his reflexes and mithrilium. Primarily, he wanted to see how his magically split focus worked when he had to focus on multiple opponents along with the spells flying at him.

Near instantly, all six fired their opening barrage at him, while at the same time Harry consciously reached out for the mithrilium in his head and told it to increase his general awareness. The result was the world suddenly jerking before everything seemed to move slower.

It was something he had been working on for a while, but was thrilled that it had worked so well. Unfortunately, it was only his perception of time that had changed, physically his reactions were actually slower given his body couldn't respond as fast as his mind.

Despite the physical limitation, it gave him more than enough time to identify each of his opponents spells and come up with a way to counter them. On his far left Ron had fired a Jelly-legs and a boils jinx, both of which were fairly weak but extremely quick and annoying if they hit. Next to him, Luna had fired a levitation charm and was in the process of a general shield charm.

Neville had gone straight to a powerful stunner, although Harry could tell the spell was going to go wide. However, it did temporarily limit where he could dodge to. Draco had started with a Petrificus Totalus followed by a wide area blasting curse, both of which were moderately powerful. Beside him, Crabbe had gone with an Expulso and Incendio.

Finally Daphne had fired a Glacio at the floor beneath him, followed by a Freezing curse straight towards him and then was mid cast for what looked like an ice spear conjuration. The fact that she was fast enough to get three spells done in that stretch of time managed to impress him, even if she had gone for three extremely similar spells.

Deciding to show off, Harry dropped his heightened awareness and summoned a large shield, which was able to tank all eight spells along with directing Crabbe's fire spell into Daphne's ice spear. Unfortunately Daphne's first ice spell hit the floor just short of the shield, spreading a layer of ice all around Harry. Normally, this would pose a serious threat, however the layer of air Harry permanently kept under his shoes allowed him to walk unhindered over the ice.

With some pride Harry noted that Luna's shield was big enough to cover not just herself but also Ron and Neville on either side of her, even if the top of Ron's forehead poked out over the shield. Moving to the side to dodge Neville's more accurate Expelliarmus, Harry cast two strong stunners at Luna then six successive colour changing charms, each perfectly aimed for the six opponents.

It was one of the first lessons Tonks had drilled into him, it didn't matter how strong your spell was if it was going to miss due to lack of aim. They had quickly found that Harry's aim had grown to be shockingly accurate, such that he could account for his target's trajectory.

Luna's shield was able to withstand the first stunner but shattered on contact with the second, taking the spell with it. It was only due to her crouching upon the destruction of her shield which allowed the paint charm to fly over her head, allowing Ron to be the first to 'die'.

Having foreseen the charm, Neville had stumbled out of the way. Having seemingly underestimated his dodge, Neville almost managed to get hit by the charm that was meant for Draco, only being saved by the brief shield Draco had cast in time. To his surprise, Crabbe had managed to duck under the charm and fire a retaliatory tickling jinx, showing a deftness Harry hadn't expected.

Daphne had merely lifted her right arm and shifted her body to the side, letting the spell pass with barely an inch of clearance. The result was that she ended up side on, with her dominant left hand pointing right at him as her wand released a cloud of icy air.

The cloud itself wasn't enough to disrupt his vision, but given it was formed entirely of magic it gave the cover to use a notice-not. He could tell enough to know there was a notice-not, but through the cloud he was unable to pinpoint her location. The charm was also able to give her spells a few seconds noticeability, giving him less time to react.

Especially given Neville and Draco had teamed up to send a near constant barrage towards him, where they would take it in turns to cast spells towards him. In terms of power they were easily dealt with, but there wasn't enough time in between blocking to focus entirely on Daphne.

While this was going on, he also had Crabbe's blasting and fire spells to deal with, along with the few charms Luna would send his way. It was clear Luna was the least into the fight, putting the least amount of magic into her spells. Despite that, she was one of his biggest threats, due to the fact she had yet to use the same spell twice.

Luna might fire a freezing charm, then switch to a heavy-weight charm, then onto a Beating Wings curse. This made it exceptionally difficult to predict her next spell, in turn demanding a significant amount of his attention.

Out of the corner of his eye, he was able to make out a section of the cloud shift aside, prompting him to send a wide wave of force at his opponents. The wave was strong enough to knock all four of them onto the floor, although he couldn't capitalise on this as he was forced to dive to the floor the side seconds before Daphne's stunning spell would've hit him.

Unfortunately for her, casting at such close range disrupted her notice-not, allowing him to easily make her out. From his position on the floor Harry tried to kick her legs out from under her, while simultaneously launching a wave of green paint towards her.

Twisting awkwardly, Daphne was able to avoid the paint but was unable to avoid the kick. Her hasty shield charm was enough to block his retaliatory colour charm, giving her time to backtrack and shuffle away. This gave Harry room to get to his feet, while starting his own attack. A series of stunning and disarming curses followed her retreat.

Suddenly his mage sight was screaming from his left, giving him just enough time to leap out of the way of Draco's stunning spell. Now that all five of the survivors had regrouped and stood up, he was forced back on the defensive.

Again, he noticed Daphne was limited almost entirely to ice based magic, while everyone else used at least two distinct magical families. By limiting herself to just the familia glaciei spells, he could easily counter her with a rival family, such as the familia ignis variant of Protego.

Slashing his wand, he sent another wave of force at the five of them, which gave him the time to cast a standard Protego and anchor it to the ground. With the shield anchored, he was able to begin incanting the fire variant of Scuta Comburet Igni. The wand movement was a semicircle which led into the outline of a flame.

Glancing briefly at his Protego, he was relieved to see even under their combined assault he still had a few moments before the shield broke. With the fire shield now fixed to his wand, he began the tricky modification which would anchor it himself instead of his wand, allowing it to feed off his magic while keeping the use of his wand.

The downside with the fire shield was that it was around the size of a door, meaning if Daphne stayed in front of it he couldn't get hit. Of course, if she moved even a foot to the side she'd have a clear line of sight again. Pointing his wand at her, he fired a succession of tagging charms, each of them near invisible and extremely fast.

As such, she was hit by all the charms, given she was far too slow to react. While the charms were fresh, Harry modified the fire shield so that it would constantly point towards the tagging charms, while still orbiting him. With the shield complete, Harry released a wave of fire.

He knew the fire wasn't hot or slow enough to actually hurt his friends, but it would make them panic along with completely hiding him from view. From behind his temporary screen he fired a colour charm at the last where everyone had last been standing, getting a surprised grunt from Crabbe. With the fire dissipating, Harry launched into the offensive.

With Crabbe also out of the picture, Harry created four rubber balls, which were enchanted to paint anything it touched green. It was one of the training spells the Aurors used in place of the really Dark curses, seeing as the balls could safely act like certain curses without the risk.

Neville, Draco and Daphne all fired spells at him, of which Neville's missed and Daphne's failed to penetrate his fire shield. Draco's dancing curse was easily blocked, which gave him time to launch the balls.

Neville and Luna were protected by Luna's shield, while Daphne shot her ball out of the sky. Draco sidestepped the ball and raised his wand to fire only for the ball to rebound off the arena duelling pit shield and hit the back of his head, painting him green as he was sent flying forward into a thankfully cushioned floor.

He noticed Daphne was starting to send a curse towards him, only to then dive to the side. He only realised her intention when his shield moved to follow her, leaving him open to the curse. In return, he stepped to the side to put the shield back into the path, while also modifying the shield to become wider. It would take more power to keep it up, but it wasn't like the duel was going to last much longer.

As Luna moved to get in between Neville and Daphne, he erected another wave of fire, this one used to split Daphne from the other two. While he would keep an eye on Daphne, who still hadn't swapped from ice-based spells, the fire would let him focus on Luna and Neville. Now that he wasn't testing their offensive, he didn't hold back on power.

His first stunner impacted Luna's shield and burst through it, shattering both in the process. Neville's bubble shield absorbed the following colour charm, but accidentally blocked Luna. With Neville's shield on her right and the wall of fire on her left, she had nowhere to go as the colour charm tagged her right on the stomach.

Having seen he was focusing on the other two and that her spells were being blocked, Daphne had moved onto attacking the wall of fire. Her freezing charm managed to vanish the wall only after Luna was shot, in time to step in and help Neville.

When forced on the defensive the blond boy was surprisingly strong, such that without his mithril Harry would've struggled to over power them without draining himself. As it was, he had both his mithril and his creativity.

Sending a stream of green gas at Neville, Harry summoned a spark which ignited the gas, dealing a significant amount of damage to the shield while also temporarily starving the area of oxygen.

Moving to Daphne he began his own bombardment of blasting curses, stunning, disarming, petrifying and fire. Every so often he would add in a random charm, to prevent her from knowing what he was going to use next. Her shields were around as strong as Neville's, although hers were far more exotic. One was a wall of thick ice, another was the ice equivalent of his fire based shield.

Throughout the attack, he had only seen her use a conventional shield twice, which had been considerably weaker than her other shields. Out of the corner of his eye he saw Neville start to emerge from behind the smoke, prompting him to summon and launch a ball towards the floor below him. He had timed it perfectly so that as Neville dropped his shield to help Daphne, the ball bounced off the floor and struck him in the stomach.

Moving back to Daphne, he sidestepped her frozen-feet curse and summoned a wave of fire close to the ground and sent it towards her ankles, then formed a wave of green paint and launched them just above her head. As expected, she jumped over the fire, saw the wave of paint and panicked.

Her shield successfully froze the paint, however the shield did nothing for its momentum or path. The frozen paint smacked into her face, covering her in paint.

"Harry wins." Ron said disappointedly, having been hoping to watch Harry get defeated, even if he got hit first.

"Right, if you're all up for it, I'd like to point out what I noticed. Now, Ron; I didn't actually mean for you to get hit so quickly, so sorry about that. However, it did reveal that you need to work on your situational awareness. Just because an ally has a shield up, don't blindly rely upon that shield. As I demonstrated, shields can fall, so it's important to know what might hit you at all times.

"Neville, you also need to work on your situational awareness, specifically when dodging. At the start, you almost managed to jump out of the way of one spell and into the path of another. You would've also gotten in the way of Draco casting, which if he'd been casting a blasting curse then you'd both be dead. Other than that, the power behind your spells and shields are great, we'll just need to focus on improving your aim.

"Draco… to be honest I don't have much to say. Your power isn't quite as strong as Neville's or Daphne's, but it's still good enough. Your reflexes are good, your aim is consistently accurate and your teamwork is great. You just need to remember that just because something has passed you, it hasn't stopped being a threat. I could've thrown a knife and then summoned it once it was behind you for instance."

Draco puffed up with pride at that, even if he seemed annoyed he had been defeated.

"Crabbe, your speed could possibly do with improvement, as could power. Reaction times could be improved, along with shielding. When your visibility is low, I'd advise having a shield charm ready to cast, just in case a spell catches you by surprise.

"With the possible exception of Ron, all four of you could do with more variability. You will also benefit by using shields specialised for the environment, such as a physical shield to stop physical attacks and a purely magical shield for spells. Those shields take less power to cast, along with being stronger. A general shield like a Protego is only really better when faced with multiple attacks, where you can't tell if you are facing a physical or magical attack. Luckily, both those issues can be easily fixed by just learning more magic, which I'll happily help with."

Turning to Luna and Daphne, he took a breath, knowing they were the two who needed the most improvement.

"Right, Luna, we need to work on your offensive. Being the protector or even healer of a group is great, but most of the time a good attacker is better than a good defender. When I was pushed on the defensive, you had no reason to keep your shield up. That would've been the time to unleash your stronger spells in a hope to overpower me, instead of relying on a stream of basic spells.

"Your variability is excellent, you just need to work on adding more powerful spells. I know you'd prefer to avoid hurting someone, but sometimes you don't have that luxury. If you want, we can work on spells that simply trap an opponent, instead of harming.

"Daphne… you need to use a wider variety of magic. Your ice based magic is easily the strongest here, but that's completely pointless once your opponent has figured out you stick exclusively to the ice magic. If we had been duelling one-on-one, I probably could've beaten you in a matter of moments."

"I disagree, there were times when I was winning!" Daphne cut in hotly.

"Do you want to prove it?" He returned, beckoning towards the duelling platform.

"... Not right now. When I've had a chance to regain my strength then we'll fight."

"If you insist. Although that does bring me excellently to my next point. All of you ideally need to work on your stamina, such that you can have several duels back to back. Part of that is knowing when to reserve power and when to go all in to end a fight. After all, there's no point reserving magic only for your opponent to receive reinforcement. Likewise, in something like a duelling gauntlet; if you win your first fight by wasting most of your energy, then you're probably going to get beaten in the second fight.

"Leylines, we use them everywhere, almost everyone has heard of them, but what actually are they? Would anyone like to tell me what they know about them?" Bathsheda asked once everyone had settled down.

Beside him, Daphne stuck her hand up, drawing Bathsheda's attention. Harry had been surprised when she had decided to sit next to him, although her challenging glare persuaded him not to question it.

"Yes, Ms. Greengrass."

"Well, leylines are the magical lines which provide magic to the world. Hogwarts is rumoured to have been built atop three leylines, which is why the wards are so powerful."

"Good, take five points to Slytherin. Unfortunately you are not entirely correct. To start with, leylines do not provide magic to the world, for instance there are no leylines around Northern Asia. Despite that, they still have more than enough magic. To start with, you need to understand there are two types of magic, Atmospheric Magic and Activated Magic.

"Atmospheric magic is made by the nature around us, anything from the trees to the very ground all give off atmospheric magic. This magic is used by every living creature, where it is turned into activated magic. The world then takes in that magic and turns it back into atmospheric magic in an endless that final process takes considerable time, meaning it can sometimes take years for the world to turn activated magic back into atmospheric magic. Leylines can do the same process in a matter of days.

"Now, runes can be made to use either atmospheric or activated depending on the need, however so far we have only covered activated runes. This is because they have to be activated by a witch or wizard, along with only being limited by the amount of magic given to it. Atmospheric runes can be automatically activated the moment the rune array is complete, with potentially unlimited power.

"For example, if you created a rune array to conjure fire. Now, if you got it wrong you would first have the chance to catch the mistake before activating it, but even if you missed that the runes would eventually run out of power. However, under an atmospheric array, you wouldn't have the chance to catch the mistake once finished, resulting in a ball of fire that will keep growing until whatever the runes were carved upon broke."

Many around Harry looked incredibly nervous at the idea, with good reason. Ever since Bathsheda realised his mithril ran on atmospheric magic she had drilled him on all of the dangers, along with the best ways to shut off such magic. Later she had realised his workshop had ended up being one of the safest places to use atmospheric magic, since he could shut off the magic passing through the walls at a moment's notice.

"Now, the second thing wrong with Ms. Greengrass' statement was regarding Hogwarts being built on three leylines. 'Hogwarts: A history' clearly states Hogwarts was built on top of two adjacent leylines, with a third running under Hogsmeade village. It was only several decades after Hogwarts was built that the leylines ended up converging. Now, what does this tell us?"

"Does… does it tell us that the leylines move over time?" Susan Bones asked tentatively, as if afraid of being wrong.

"Exactly, take five points to Hufflepuff. Now, Ms. Greengrass was correct in that leylines bring more magic to an area, allowing places like Hogwarts to utilise stronger wards. However, in turn they are fed by places that generate a lot of activated magic, such as a school of magic. As such, much like the tree's roots move to find the closest water source, leylines shift towards the biggest source of activated magic.

"Of course, wards can be strong without the presence of leylines. Such as the great Chinese citywards, each of which are rumoured to be at least as strong as Hogwarts, despite the fact they have to deal with a considerably larger area and the complete lack of leylines. However the time it would take the wards to assemble and bleed energy would take considerably longer. Now, the reason I bring this up is because today we will be learning how runes can tap into leylines."

I had planned to upload last Friday, however events conspired against me such that I was unable to sit down and finish the chapter until today. With luck I will be able to upload the next chapter on the second Friday as per normal.

Thing I think I need explaining:

The duel: Harry was holding back. He wasn't using his mithril aside from replenishing his energy and he certainly wasn't putting his full power behind either spell or shield. The aim of the duel was to allow him to figure out where everyone needed improvement. If he was properly trying then all six of them would've been stuck trying to get through his mithril shield while he sniped them with his spear.

Magical families: After almost two years, they are finally prominent again. So far they have remained largely unimportant, however I wanted to show Harry still retained the knowledge. The elemental families will work on the Rock Paper Scissors type of balancing, such as fire being strong against ice and grass while weak to earth and water etc.