AN: This story will, in essence, be a side-story to what could have been Harry Potter, if one of the 'competent' adults in the series had been replaced with a character that was actually written, like a competent adult. I will also be using it to test out some concepts for Brutal Harry's sequel, so some content might hold over, but no promises. Expect a great deal of applied psychology, general, child, and developmental. That is what this story is for, to show how some fields that people consider 'for the academics' are actually critical to everyone's life, every day.

((()))

Harry looked up at the staff table, and two professors in particular caught his eye. The first was one wearing a ridiculously large turban, whose face he could not see, because the man was looking away, with the back of his turban directed towards Harry. The second was a young man, Harry estimated to be in his mid twenties, who was wearing normal clothing, rather than the robes that Wizards favored. As he watched, the second professor turned and met his gaze, looking at Harry with an intensity that surprised the boy.

Then Harry felt a sharp pain in his scare, and broke eye contact.

((()))

"Come in, everyone, and sit down," The man said as the Slytherins filed into their common room for the first time that year, "I am Isaac Trailbreaker. Those who have fought me in full-contact spars, or survived me in real combat, frequently call me 'Bandersnatch.' I am your new head of house."

He spoke with a very faint American accent, so faint that only half of the students even noticed it, and stood tall at six feet two inches, with short brown hair, blue eyes, and a clean-shaven face that was neither particularly handsome nor homely. In fact, the only particularly notable feature about him physically, was his height, and that he did not wear wizarding robes. As the Slytherins seated themselves about their rather austere common room, however, he took the time to lock gazes with each and every one of them, and many found the intensity of his scrutiny unnerving. His bright red shirt and dark blue pants were particularly jarring as they clashed heavily with the finely-crafted furniture and adornments of the room, all done in silver or green.

"I am sure many of you," He said, voice projecting clearly through the common room as he began to pace about, gaze moving from student to student, "Particularly those with an affinity for Potions and returning students, are curious as to what has happened to Severus Snape, your former head of house and Potions Professor."

A number of the students nodded, particularly the prefects and one Draco Malfoy.

"The answer to that question is simple," Trailbreaker said, "By happenstance, Snape and I were both in Brazil late this summer, I on retainer to a cursebreaker expedition, I believe Snape was collecting potions ingredients. We came into conflict over his treatment of one of the local laborers, and he chose to initiate a fight with me. Then he chose to begin using lethal spells."

He swept a hard gaze across the entire assemblage of students.

"I am a fully certified Battle Mage within the American system of magic," He said harshly, "Something that roughly translates to a Defense Mastery within the European system.

"I killed him."

Shocked gasps rose up from within a large segment of the Slytherins, and some of the older students faces revealed blooming anger. Trailbreaker took a moment to outright glare at each of these students, especially Marcus Flint, and Draco Malfoy. Malfoy was cowed, but Flint rose to the challenge.

"If you killed him," Flint demanded as he stood and lay his hand on his wand, "What are you doing here, instead of in Azkaban?"

"Because, student of mine," Trailbreaker said harshly, glaring at the boy, "We were in Brazil, not in England. He attacked me with lethal magic, after I warned him that I was a certified Battle Mage. More, he was firing off lethal spells in an occupied marketplace. I was arrested, and brought to a court hearing within Brazil for my involvement in the incident. I was cleared of any wrongdoing, and, in fact, rewarded for ending a threat to the public. A dozen people were injured, some of them very seriously, before I killed the man."

"I don't believe you," Flint snarled, glaring right back at the man.

"That's perfectly fine," Trailbreaker, "But understand that you have been warned. When you take up a wand to attack another, I will respond with force, and force proportionate to the spells you cast. As part of my employment agreement with Dumbledore, I will not respond to potentially lethal spells directed at myself with similar force, but if you use such spells on another student, I will."

The staring contest between Flint and Trailbreaker continued; Flint discomfited by the older man's words, but unwilling to lose face by backing down. The issue was made moot, when one of the other students decided to attack Trailbreaker from behind.

"Stup-" Hector Gamp shouted out, as he rose from his seat, wand in hand.

Isaac had started to move before Gamp's wand was even drawn, pivoting in place and lashing out with an empty hand, silently banishing the sixth-year Slytherin across the common room into the wall, summoning his wand out of his hand before the boy even struck the wall. Flint tried to use the opportunity to get the drop on Trailbreaker, but the older man spun in place, bringing his leg up into a high kick that not only smashed Flint's wand out of his hand, but broke his wrist and three of the bones in the process.

Flint screamed, clutching his pulped right hand, with his still-intact right, completely taking his attention off of Trailbreaker, which made it much easier for the new head of Slytherin house to slam his fist straight into Flint's nose, smashing it, and unbeknownst to the other Slytherins, delivering a contact stunner that rendered the boy thoroughly unconscious. As the boy fell, Trailbreaker delivered two rapid-fire side kicks to Flint's knees, shattering both of them, then once the boy was on the floor, he stomped on both elbows, breaking them, before very pointedly flashing a visible stunner from his bare hand into the boy's insensate body.

He then turned and summoned Gamp across the room towards him, bracing himself, then slamming his left fist into the boy's gut, folding him over. Isaac then pounded both of his elbows into the back of Gamp's head, a contact stunned again rendering the boy unconscious, before breaking the boy's nose against his knee, and hurling the collapsed body down onto the floor beside Flint.

Utter silence reigned in the common room.

"Would anybody else care for a try?" Trailbreaker said in a quiet, deadly tone of voice, as he wiped blood off of his knuckles.

Nobody dared say a word.

"When a teacher," Trailbreaker continued in that same quiet tone, sweeping his gaze across the other students, all of whom were white-faced, and some of whom were trembling, "Especially your head of house, asks you a question, you respond to it. I will ask again, would anyone else care for a try?"

Again, no one responded.

"The two correct responses," Trailbreaker said, "Are either 'Yes sir,' or 'no sir.' Every student in this room who has not responded with one or the other in the next sixty seconds, I will assume has chosen to challenge my authority," Trailbreaker gestured to the two students at his feet, "Like these two down here,"

A cavalcade of 'No sir's' washed over the common room, and Trailbreaker swiftly looked about, to make sure everyone had spoken.

"Note here," Trailbreaker said in a more normal tone of voice once they were finished, "That I both used non-lethal force, and that I did not attack until they did. I desire your respect," He swept his gaze across the room once again, "But if you will not respect me for who I am, I will not pander to your tastes. I am now an authority figure over you, and am thus charged with enforcing both the peace, and a set of rules. If you will not respect me, then you will fear me. If you do not initiate violence, like these two idiots, then you have no need to fear violence from me."

No one said anything as he swept his gaze across them for the final time that night.

"Alright then," He said, "The seventh year prefects will take these two to the infirmary. Goodnight."

And with that, he left.

((()))

The first staff meeting of the year, held the next morning, was mostly the usual laid back affair amongst the teachers, with a slight bit of uncertainty over Snape's replacement. At least, it was until said replacement arrived at the meeting.

Then things became incredibly tense.

"I'm curious," Isaac said as he walked into the cozy staff room, radiating a silent aggression, then sat between Flitwick and Filch, the seat Snape had occupied during staff meetings in the past, "As to what the expected qualities of a Hogwarts graduate are?"

"Well," Dumbledore said jovially, utterly ignoring Trailbreaker's aggressive and tense body language, "Certainly they should have performed competently on at least three OWLS and NEWTS, and be prepared to function as happy, constructive members of Wizarding England."

"That's strange," Isaac said after a moment had passed, "Because after having gone over the student records, and now having met myself, I had come to the conclusion that Hogwarts deliberately trained Gryffindor's to be vigilantes, Ravenclaws and Hufflepuff's to be victims, Slytherin's to be hardened criminals, and all of them to have absolutely no respect for authority whatsoever."

All activity, and all sound, within the staff room came to a dead stop.

"I don't suppose," Dumbledore eventually said, "That you would care to explain exactly how you came to this unfortunate conclusion?"

"It is very simple," Trailblazer said, "The Slytherins have been permitted to run rampant within the school, verbally and physically abusing the other students, while their head of house protected them from any consequences or retribution greater than a slap on the wrist. Save for when Gryffindor students took matters into their own hands. This seemed fairly obvious from what I read in the school records of various incidents and punishments dealt out for their behavior. However, I did not wish to draw premature conclusions without direct experience. Then two of my new house members attacked me."

Sprout's face paled. Flitwick became very still. McGonagall's expression became particularly stern. Filch scowled. Sinistra shrank slightly in her seat. Vector's lips pressed into a painfully thin line. Grubbly-Plank looked like he was fighting back laughter. Babbling appeared uncertain how to react. Trewlany decided it was time for more Sherry. Pomfrey already knew exactly what had happened, and wasn't sure whether to glare at Trailbreaker or not.

Dumbledore merely looked concerned.

"I hope you weren't too stiff in rebuking them," He said with a slight hint of worry in his voice.

"Nothing Pomfrey was unable to fix by morning," Isaac said evenly, "But sufficient that I do not expect to experience discipline problems again in the near future."

"What is it that your students chose to attack you over, anyways?" Flitwick asked curiously.

"I informed them of the circumstances surrounding my employment here at Hogwarts," Isaac said, "They were attempting to deny the truth, and acted violently. I had not even begun to talk about how things would be changing under my leadership," He turned to face Dumbledore, his voice becoming incredibly harsh "Tell me, Headmaster, do you think the little cadre of criminals you've been training down there might have been pushed over the edge by racism, because I'm American?"

Albus Dumbledore, for the first time in the memory of any of the currently present staff members, became visibly flustered.

"It has been a long time since someone has deliberately baited me," He said with some tension in his voice.

"Well," Isaac said harshly, "It has been a long time since I have visited a murder factory pretending to be an upstanding center of education. One could say I had never been to such a place before. On any other continent, you would be under investigation to see if the handling of the school thus far was due to gross incompetence, or deliberate malignance. Have none of you studied Psychology at all?"

An embarrassed silence filled the room, Professor Babbling hesitantly raising her hand.

"A little," She said, her voice faint with something a shade short of fear.

Isaac closed his eyes, and began massaging the bridge of his nose with his left hand. Taking several long, deep breaths before speaking again.

"I have no authority to command any of you," He said, still not opening his eyes, "But I will be acquiring a number of volumes on human psychology. I strongly suggest that you all read them. It will be much easier for me to shape this place up if the rest of you are working with, rather than against me."

Then he got up from the table, and left. Silence reigned in the staff room for some time.

"Well," McGonagall said with a scowl, "There is an arrogant young man with a great deal of presumption, and little in the way of manners."

"Really?" Flitwick said, turning to face the larger Witch, "Compared to Severus?"

"For all of Severus unpleasant personality," McGonagall said, "He never presumed to question our teaching methods, or the Headmaster's administrative practices."

"He hardly suffered for us to do the same though, did he?" Sprout said, "I would say that Mister Trailbreaker being arrogant or presumptive, is entirely dependent upon whether or not he's right wouldn't you?"

"I suppose," Dumbledore said with a nod, "I will note that Isaac did not question the validity of anyone's teaching methods, but the validity of our disciplinary methods. While I quite object to the blunt manner of his communication, I believe that in all fairness, we should give him a chance to prove himself."

"Well," McGonagall huffed, "His manners are still abysmal."

((()))

The first thing Isaac had done once he had completed working through his curriculum, was rearrange the entire class schedule for potions. The primary difference, was in grouping each year together in their entirety, all four houses at once. The second, was the scheduling of the classes; First Years together Monday morning, Second Years Monday after lunch, Third, Fourth, and Fifth years on Tuesday, Wednesday, and Thursday mornings respectively, and the much smaller sixth and seventh year NEWT classes combined in two periods, directly before and directly after lunch.

His intention was to persuade the House Elves to feed them in the potions dungeon eventually, and work clear from nine AM, to four PM, allowing a more comprehensive and immersive learning experience.

Before any of his grander plans can proceed though, there is his first class, with his first batch of students, the first years.

"Good morning everyone," Isaac said pleasantly once the students had all arrived, and class period had begun, "I am Isaac Trailbreaker, Hogwarts new Potions instructor, and as you have no doubt already noticed, I am running things a little bit differently."

He paused a moment to let the students soak that up, some of them nodding, before continuing.

"In this class, you may address me as either 'Teacher' or 'Mister Trailbreaker,' as I am not, in fact a Potions Master, though I am more than sufficiently qualified to teach the subject, my true area of specialty is what you would call Defense. As my new students in Slytherin have already learned."

He paused again to sweep his gaze across the corner of the dungeon where the Slytherin's had seated themselves, not threatening, but warning.

"Although none of you have experienced my predecessor's, teaching methods," He continued, "I expect that all of you, particularly the first generation magicals present, have experienced formal lessons of some sort before, even if only from your parents, so you may find my teaching methods to be strange. First off," He said, moving to his desk and seating himself atop it, "Raise your hand if you're familiar with the term 'Critical Thinking.'"

Seated on his desk, he was perched high enough to see all of the students clearly in spite of how tightly packed the dungeon was. To his disappointment, but not surprise, only four students raised their hands; Hannah Abbot, Susan Bones, Hermione Granger, and Dean Thomas. It was a rather sad showing, out of a class of forty.

"I suppose that isn't exactly surprising," He said, "Starting with Miss Abbot and Miss Bones," He said, gesturing to the two girls who were seated together, "Where did you learn about it?"

"My auntie is the head of the Department of Magical Law Enforcement," Susan Bones said, "I've asked her sometimes about her work, and she taught me some about how to figure out what people are thinking."

"I was with her for some of those conversations," Hannah Abbot added hesitantly.

"That's good," Trailbreaker said with a nod, "What about you, Mister Thomas?"

"My mum follows politics," Dean Thomas said with a small smile, "Gets quite passionate about it. Insisted on teaching me and all of my siblings how to look through what people are saying, to what they're actually doing. Irritated some of my teachers right smart in primary school."

"Ah, a woman after my own heart," Isaac said with a smile, before turning to the bushy-haired girl in the front row, "And you, Miss Granger?"

"I read a great deal," Hermione Granger said, "Critical thinking was covered in some of the Logic texts I read."

"Very good," Isaac said, nodding, "Understanding is a treasure without price. Now, for the benefit of those of you who are not familiar with Critical Thinking, I will now explain it for you."

Trailbreaker stood again, and began pacing back and forth in front of the class, voice beginning to rise as he spoke.

"Critical Thinking is defined by many different people in slightly or substantially different ways, but the definition that will matter for you while I am teaching you, is fairly straightforward. Critical Thinking is questioning, testing, and reaching the fundamental relevance of something. This is something that is useful in every field of life, not just Potions, and I hope you will learn it and apply it equally well in your other pursuits. Now, I will begin teaching you Critical Thinking with an example."

He stopped, ran his gaze across the entire class, and then focused on Hermione.

"Tell me, Miss Granger, why are you taking a class on Potions?" He asked.

"Because it's a part of the Hogwarts core curriculum," Granger said promptly, in the manner Isaac was accustomed to seeing from those who took to academics like a fish to water.

"Of course," Trailbreaker said, nodding amiably, "So why is it a part of the Hogwarts core curriculum?"

Hermione opened her mouth to respond, and rather abruptly realized she didn't have a ready answer for that. It did not take her long, however, to formulate one.

"Because Potion-making is one of the primary magical disciplines, and is used in a number of professions," She said after a moment's pause.

"A reasonable enough answer," Isaac said pleasantly, "So why is it considered one of the primary magical disciplines?"

"Er," Hermione said, beginning to be a bit flustered, "I'm not really sure, Mister Trailbreaker."

"Well then," He said, no rebuke in his voice at her lack of answer, "Perhaps you can explain why it is taught as a core class, rather than an elective, if it is used only in some professions, rather than all?"

"Um," Hermione said, now quite flustered, and getting a bit panicky, "I really don't know, it wasn't covered in any of the textbooks, or any of the supplementary reading I did, and-"

"That's quite alright, Miss Granger," Isaac said gently, cutting off the girl's ramble before it could gain much momentum, "My intention was to ask you reductive questions until I found one you could not answer, and you acquited yourself quite well for a first year student, as well or better than any others I have asked such a question without prior teaching."

Hermione nodded and calmed a bit, though she was still unsettled by not having an answer to an instructor's lesson.

"Now," Trailbreaker said, addressing the class at large once more, "Does anyone else have an answer to either of those questions? Why Potions is held as a core discipline of magic, or why it is taught as a required class, rather than an elective, if it isn't used in all career paths?"

Padma Patil raised her hand.

"Miss Patil?" Isaac said.

"Potions is considered a core magical subject because it has been around for so long, and it is comparable to Charms and Transfiguration in how useful potions can be," She said.

"Indeed," Trailbreaker said, "Very good, Miss Patil, I gather you study history?"

Padma nodded.

"Anyone care to chance an answer to the other question?" Isaac asked, but nobody raised a hand, something that didn't really surprise him.

"Considering you're all first years, and few people bother to really teach Critical Thinking, this isn't really surprising," Isaac said, "But that aside, this is why I will be teaching you Critical Thinking. Critical Thinking isn't about the answers to the questions I've asked, or any particular answers really, if you look at it a certain way, it's about pursuing those answers."

He gestured towards Padma.

"Miss Patil here, provided a reason I consider satisfactory as to why Potions is considered a core subject, however, if one wanted to push Critical Thinking to its real limits, one would take things a step further, and consult histories, and test the versatility of the field oneself, to see if she is, in fact right. Critical Thinking is about questioning and testing something, until you are satisfied that it is right. Until it is consistent logically with the evidence available."

He paused and studied the reactions of his students, some showing the dawning light of understanding, some still showing confusion.

"Another example," Isaac said, walking to his desk, and picking up the first year Potions text, then paging through it briefly before opening it wide and showing it to the class.

"This is page eighty-three of the text your syllabus requires for this class," He said, "On it you will find the recipe for the Boil-Removal potion. If I were to say that this is the single most important potion that has ever, or will ever, be invented, what would you say to that? Raise hands please."

Hermione was the first to raise her hand, but Isaac chose to call on someone else.

"Mister Finnegan?" He called, nodding towards the Gryffindor near the middle of the class.

"I would say you're trying to pull one over on use, Prof-, er Mister Trailbreaker," Seamus Finnegan said with a slight Irish lilt.

"You'd probably be right," Isaac said with a snort, "It does seem to be a rather ludicrous claim, doesn't it? When there are far more potent potions available, the Blood-Replenisher, Polyjuice, Skele-grow, Veritaserum, the Ubiquitous Healer, there are other potions with more useful effects. On the other hand, maybe the discoveries involved in the invention of the Boil-Removal potion were fundamental to every potion developed since, or perhaps it is actually an intrinsic ingredient to all of the potions I just listed. Do any of you know?"

Hermione raised her hand.

"Oh?" Isaac said, smiling and raising and raising an eyebrow at the precocious Gryffindor, "I suppose you've read far enough ahead to know that at least one of the possibilities I just listed is false?"

"Yes, Mister Trailbreaker," Hermione said.

"Very good," Isaac said, "It never hurts to be well informed, though the facts themselves may sometimes be unpleasant. The reason for this second example, is to show another use of Critical Thinking, using it to disprove fraudulent claims. If you don't know how to question something critically, a charismatic and persuasive enough person could literally convince you of just about anything. Does anybody not understand?"

A few students raised their hands, but for the most part, the class understood.

"Very good then," Isaac said, "There is an hour and a half remaining in this class, you have two assignments due at your next class session, a week from now, I do not care about the length of the assignment, but I do care about the quality of the content. If you can answer my questions well with two sentences, that will be enough. If it takes you ten pages, I will expect ten pages. If I catch you slacking and trying to turn in a short assignment, I'll grade you a lot more harshly than if you tried hard, but failed.

"Your two assignments are as follows; first, I want a paper on just what it is and is not possible to do with Potions as a whole, and second, I want a paper on what your personal reason for learning Potions is. The first is to be completed before the second, as there's no point in deciding how interested you are in a field before you understand it. My office hours and location are posted at the entrance to this classroom, and I consider consulting me about these papers, while I am in my office to be a perfectly legitimate source of information, as well as any other students or teachers you wish to.

"Now, those of you who still need some help understanding Critical Thinking can come to the front of the class and speak with me, the rest of you are dismissed, though I recommend you use the time remaining in this period to begin your assignments. If you're sharp, you may finish your homework before the class period even finishes, though don't undercut your efforts by rushing."

Hermione furiously waved her hand in the air.

"Yes, Miss Granger?" Isaac said.

"Can I speak with you when you're finished?" She asked hopefully.

"Certainly, Miss Granger," He said, "You may wait here, and we can speak on the way to my office once I'm finished with your classmates."

((()))

AN: This'll probably see occasional further chapters. As usual for anything in the Blender though, no promises.