As a child, I would often get obsessed. My obscure interests and apparent apathy toward everything else meant I didn't have close friends. Had I not been born to a noble family, my life would probably have played out quite poorly.

  I was about fourteen when I first got into hydras. Perhaps a bit late to be having a monster phase, but this particular obsession would become my life. It all started when a high-ranking adventurer party was sent to exterminate an adult hydra not far from our estate. There was always something out there in need of slaying—so plenty of work for adventurers—but normally the local nobles would have priority choice with a monster of this level. This particular hydra had unexpectedly defeated an experienced noble team. To prevent a repeat of that embarrassment, on the second attempt, it was decided that an adventurer team would be sent in first while noble and oathbound tacticians observed. My instructor at the time was among the observers and had me tag along.

  While I knew hydras got big, until that day, I had never seen one bigger than juvenile. Hatchlings are the smallest and quite common in my home country. Adults are rare, and since they tend to stay put and have relatively small territories, people seldom run into them. This particular individual was an elder which had taken position along a choke-point in an important trade river.

  I've since learned of ranks beyond ‘elder’. The ranks are: ‘hatchling’, ‘juvenile’, ‘adult’, ‘elder’, ‘ancestor’, ‘remnant’, and ‘primordial’. While it is likely the last two are myths only, the romantic in me chooses to believe in them anyway.

  The elder hydra was magnificent. Not just the size and power of it, but also the way it controlled the battle from start to finish. The way it figured out its opponent's strengths and weaknesses and adjusted accordingly with calm flexibility. As the adventurers died one by one, did they realize that this monster was smarter than them?

  Hydras are naturally intelligent. My research suggests that an adult hydra with understanding +2 would be about equal to the average human. Now, if that same adult made it past ‘adult’ and advanced to ‘elder’, it would not get any smarter with age, but it would have centuries of experience to draw on.

  Just think of the potential of such a creature! I think about it all the time. Come. Imagine it with me! A monster of gigantic proportions, near invincible, powerful, deadly, experienced in battle beyond mortal standards, and smart on top of all that. A true calamity.

  Are you excited yet!?

  It turned out, not many people understood the glory of my vision. I spent years traveling between courts, parliaments, councils, and so on trying to convince someone to back my research.

  That phase of my life took me far from my homeland, and along the way I picked up Julie. At first glance, Julie might look more like someone who would keep a cat, or a pet rabbit perhaps, but no—Julie is a monster nerd through and through. If it doesn't have scales, fangs, claws, tentacles, or really anything in that vein, Julie is just not interested.

  Let me tell you about myself. I dropped out of mage academy within a year. I had tried to become a monster tamer but lacked the aptitudes. The second time around I dropped out in even less time. I had no aptitude for biomancy either.

  It turned out that the combination of aptitudes I did have fell—to an unusual degree—firmly within the so-called ‘black magic’ field.

  There is a lot of prejudice against the dark arts. Few academies offer any courses on it, and those that do are often annoyingly restrictive about it. It is seen as more of a renegade field and not something a well-bred noble boy should pursue. Naturally, my parents were disappointed, and I lost any chance of inheriting the family lands.

  I gave up on studying and started working as a labyrinth guide. My strength grew rapidly in that time, but I lost too many charges and gained a poor reputation for it.

  Having built up my competence in navigating the labyrinth, I traveled all the way to the Akkur states and enrolled in the Ur school of black magic. All sorts of things can be bought in Ur, and the school even has a vivisection club.

  Sadly, hydras are not native to that continent, so I had to put my main interest on hold—but don't think that I had moved on, oh no! I wasn't some wet-behind-the-ears teenager joining the academy with a vague notion of finding or improving myself. No, I had come with a purpose! It had all been for ‘Project Primordial’, my quest to create the ultimate monster!

  In Ur, I learned of a substance known as activant. This elixir is extremely hard to come by. Sure, the ingredients are rare, but a bigger factor in its price is low demand.

  Drinking activant almost always results in death—and even if you do survive, the rewards are random. When administered, usually a team of high-level healers are employed to keep the subject alive. They rarely succeed.

  Activant is a lottery for the desperate. There is no potion that will increase your tolerance for it. No system-granted buff, resistance, or immunity ability helps either.

  Years after learning about it, I found an old journal detailing a study suggesting that slight natural tolerance can be built up if diluted doses are regularly administered during infancy. The researcher concluded that the tolerance gained was far too weak to be worthwhile.

  After running some calculations, the true potential of activant became obvious to me. It is useless for people, beasts, and most monsters, sure—but not all monsters! You see, hydra base regeneration is not system-granted. Though the system can enhance it well beyond its natural capacity, even a level 0 hatchling with no enhancements can regenerate surprisingly quickly.

  I arranged a meeting with my then sponsor—a small-time warlord—pitched my plan for Project Primordial, and was rejected without debate. I quit my job that same day and set off on a long journey which would eventually lead me here, to the Perlin republic.

  I don't know if I did anything different on the day I approached the Perlin parliament. I suspect it was because they had money to spare, few short-term threats, and a very long-term outlook. Perlin is a city-state located in the center of a well developed region. They accepted my project and put a staggering amount of resources behind it.

  So what does activant do exactly? Hehehe, something very unique... Something that goes against everything system theorists will tell you. But first, let me step back and give you some background.

  At every level-up, you are presented with a list of abilities to add or upgrade. The key to a good build is being offered good abilities. Now, two of the fundamental concepts in system theory are ‘achievements’ and ‘thresholds’.

  An achievement is anything you do that impresses the system. The system will offer abilities which mirror your achievements. As an example, those training to become fire mages are first taught to set enemies or the battlefield on fire by more mundane means. Do this often enough and the system should eventually offer a fire-related ability—provided you have a compatible class.

  The system sometimes mentions thresholds or achievements, but never directly exposes much detail on them. Nonetheless, their workings are well established. It has been known for as far back as records go that the same achievement will not, in general, result in the same abilities or upgrades being offered. An ability is only offered if the achievement exceeds the class-specific threshold. The same is also true for every consecutive upgrade of that ability.

  As an example, while it is possible to be offered a basic summoning ability within the archer class, the achievement needed would have to be something truly impressive. Meanwhile, the same threshold is so low within the summoner class, that simply keeping your pet rabbit alive for a week should qualify.

  Thresholds are determined by class and class alone—no further variation exists between individuals.

  Now that we've established that classes are paramount, let's consider class quality. Some classes are simply superior to others. Anyone who has reached level 10 will know that the classes you are offered are influenced by your achievements and restricted by the domains you've unlocked.

  For achievements, plenty of training regiments have been developed. Some are common knowledge, some are taught at academies, and some are closely guarded secrets within specific noble families. Domains and the way they govern classes are shown explicitly by the system. Achievements and thresholds are never directly revealed but have been thoroughly studied experimentally.

  There is, however, one essential mechanic that has always resisted investigation: ‘aptitudes’.

  When a domain pearl is consumed, the contained domain is revealed, but unlocking it is not guaranteed. When it fails to unlock, we say that person lacks the ‘aptitudes’ for that domain.

  What do we know about aptitudes? We know they are influenced strongly by species, but beyond that, all variation seems to be determined at birth on an individual basis.

  Let me summarize the dilemma: you need good abilities to fight well, you need a good class to get good abilities, you need to unlock domains to qualify for good classes, and you can only unlock those domains for which you have aptitudes.

  Now, listen closely, here comes the important bit: aptitudes are not influenced by your achievements, abilities, classes, or previously unlocked domains. You are simply born with them.

  Unauthorized usage: this tale is on Amazon without the author's consent. Report any sightings.

  Sadly, a common confounding factor that often throws laymen off when trying to explain this point is ‘system-granted domains’. It's a nuanced point, and it will probably go over most of your heads, but I will try to educate you anyway. While the domains offered at milestone level-ups are selected based on your past actions, that selection is restricted to the set which you already had aptitudes for.

  As an example, just because you were offered the (sense->sight#1) domain at the level 10 milestone after starting archery training, does not mean that continued training will necessarily lead to (sense->sight#2) being offered later on. It simply means that you had the aptitude for (sense->sight#1) to begin with, and that you were offered it ahead of others domains which you also have aptitude for because of your training.

  Now, with all that said, unlocking (sense->sight#1) is evidence that you are more likely than average to also have (sense->sight#2) in your aptitude set. And if that part sounds contradictory to you, you need to learn about belief updating—but I don't have the time or patience to teach it here and now—so, instead, to illustrate the tyranny of domains, I will use myself as an example,

  base class: human (physique->endurance#1, equipment->weapons#1)

  primary class: dark-master (influence->compulsion#4, affliction->torment#2, spirit->connection#1)

  secondary class: bloodstone-converger (preparation->ritual#3, compounds->blood#1, environment->earth#1)

  tertiary class: system sage (mind->comprehension#3, system->inspection#2)

  I know... it all sounds very edgy, but remember, all I ever wanted was to be a monster tamer. Really, even some monster-related druid class would have made me happy. But no! I got (compulsion#), (ritual#) and (torment#). And while I did not strictly have to pick a class that uses my strongest domains, not using them would have seriously limited my progression.

  My family spent a fortune buying domain pearls in the hope that I would unlock something presentable. One after another I consumed them, hoping to be offered something better. Most uselessly crumbled in my hands. The ones that did succeed were mostly in the same vein: (torment#), (blood#), (decay#)—yeah, even I don't want to be seen equipping that last one. All evidence points to my aptitudes being heavily skewed towards the so-called ‘dark arts’ cluster—hint, it's a made up category.

  I hate my aptitudes. Sometimes I imagine a different life. A life where I became a monster tamer. I would spend my days out in the woods, frolicking with my colorful band of monster companions, and we would ride off into the sunset to wreak havoc. Alas... that wasn't meant to be. Instead, I spend my time here in a stuffy tower painting tedious ritual circles in stinky goat's blood.

  Where was I? Oh, that's right, aptitudes! So this is where activant comes in—and I want you to stop and really think about how anomalous it is to our world. Activant—on the off chance you survive drinking a full dose—grants aptitudes. Exactly which aptitudes are affected is thought to be purely random.

  Now do you see? Do you see the potential? Do you see?

  Activant has the potential to completely disrupt the build templates that have defined our world for thousands of years! I've brought this up with other researchers, but they always retort that, "iT dOeSn'T mAtTeR bEcAuSe ThE sUrViVaL rAtEs ArE tOo lOw~". It is a good point. But I have a simple answer: I don't care about using it on myself or any other person. I want to create the ultimate monster. And this, this is where hydras come in!

  There are several known species with strong natural regeneration. Of these, hydras are the most numerous. How so? Well, adult hydras are huge, but their eggs are tiny. A mature hydra female can lay more than a hundred eggs per year, and that number grows as she gets older and bigger. There is no child-rearing for hydras, only survival of the fittest, and out of a single batch, it is more likely than not that all will perish without reaching adulthood.

  Hydra hatchlings are easy to supply and thus the best candidates for activant experimentation—aside from also being the coolest. For just over fourteen years now, we've been feeding them diluted activant to build up natural tolerance. These doses we use would easily kill a bear, but despite being effectively infants, and small enough to pick up with just one hand, these creatures simply walk it off. We also found that feeding them mimic meat helps suppress some of the long-term negative side effects—though, they refuse to eat it unless you starve them first.

  Up until very recently, the activant doses we've administered have been far too small to grant aptitudes. All this preparation has simply been to get a slight increase in their natural tolerance.

  Okay, now, to truly understand my work, I'm going to need to give you some numbers. I know, I know. Boring! Scary! But this is about monsters! So bear with me.

  With the assistance of a team of high-level healers, your typical human has about a 1 in 30 chance of surviving a single effective dose. That means you need to repeat the exercise about 30 times to have a good chance at one success.

  Now, a single success will raise random aptitudes once, but there is no guarantee the subject ends up with a better combination than, say, the average honors student at your local academy. To create something that truly surpasses nature you need multiple separate doses.

  We've done enough tests to believe that survival for the same individual at separate administrations is statistically independent, or close to it. That means that for the same person to survive the process across 4 separate administrations, the odds are just under one in a million. Obviously not practical.

  The decay rate of 1 in 30 is the crucial variable here—30 to the power of 4 being on the order of a million—as I'm sure you already knew.

  Let's now repeat this same calculation for a hydra that has undergone our prepping process. Their survival rate for a single effective dose is about 1 in 3. That means about one individual will survive the process 4 consecutive times out of every 81 subjects. Continuing the calculation for larger numbers, if we want 1 survivor in expectation, 243 subjects are needed for 5 doses and 729 for 6.

  Do you see what this means? It means: activant and hydras are made for each other! No way will you ever collect a thousand troll babies to experiment on, but hydra hatchlings? easy!

  Okay, so in theory it was all going to be easy and simple, but here we are more than a decade later and only nine have survived the third administration. Hydras have very long lives. It took us this much time just to get them to approach the level 10 milestone. While not all subjects have fully reached the activant tolerance ceiling—because the first system granted domain pick occurs at level 10, we've decided to commence the first full administrations just before then. Then, to save costs, we will start feeding them domain pearls just before the level 20 milestone.

  In my thirties, I tried to track down that suspected understanding +2 hydra elder from all those years ago.

  After analysis of the fight against the sacrificial adventurer team, a noble team had been assembled to finally end it, but they would be left unsatisfied as the monster had quietly disappeared without a trace.

  While some speculate that it must be dead—or we would have heard about it reappearing by now—I choose to believe that it went into hiding because it knew what was coming and decided to bide its time. Surely it is still out there, somewhere, patiently planning something sinister as we humans go about our comparatively short lives.

  The understanding ability is governed by the (mind->comprehension#) domain, so thresholds for it tend to be lower under classes that have (mind->comprehension#) as a requirement. My own system sage (mind->comprehension#3, system->inspection#2) class has gotten me to understanding +3, which is quite a feat for a human, but also illustrates just how hard that particular ability is to level when you consider my age.

  There are certain classes that are known to have low thresholds for the understanding ability. I've dedicated my life to learning all there is to know about hydras and am convinced that they never have (mind->comprehension#) in their aptitude set, nor are they prone to be offered non-(mind->comprehension#) classes with lowered thresholds for the understanding ability.

  That hydra elder had no such class and could only have gained understanding +2 by achievement alone. What exactly could it have done that was so clever that—despite the abysmal threshold—the system offered it understanding +2? I will likely die never learning the answer to this question.

  Cuddles was our first candidate to reach level 10. Optimistically, I had hoped she would pick a (mind->comprehension#) class due to her habit of sniffing out opponent weak points. Alas, while we can never know what domains she was offered—or if the activant even granted the (mind->comprehension#1) aptitude—she ended up choosing venomguard (affliction->poison#2, physique->constitution#2), a disappointingly generic path for hydras.

  Second to level 10 was Widowmaker with wind runner (physique->speed#1, environment->air#1), a ridiculous choice for a creature with such low base speed, but also confirmation that the activant worked. (environment->air#1) has never been observed in any hydra—and trust me—the records go wayyyy back for this type of thing. Bestiaries get copied a lot, and tend to even survive the dark age cycles.

  Realistically, I doubt any of our candidates will get to (mind->comprehension#1) without domains pearls. Their tactics aren't that clever, and there are so many more useful things that could be offered to a level 10 hydra.

  I'm trying not to get my hopes up too much for Deluge... but who am I kidding? Today I am as excited as a child on gifting day! At first, Deluge seemed like a weak candidate. In every fight he would use the same tactic as his first. He let himself be beaten to within an inch of death, wait for the opponent to let their guard down, and then rapidly healed while jumping forward for a constricting attack.

  Hydras are traditionally more biters than constrictors, but Deluge loves coiling himself around things. Due to his boring tactics, the monster ended up with nothing but regeneration and basic wrestling abilities. Pitting Deluge against an opponent that couldn't be constricted was a big gamble, and oh my stomach ached watching that fight.

  Deluge's weird predilection for gripping things turned out to be a blessing in disguise. Without any prompting from us, and without even being in the top-secret brain-training program, Deluge just started using tools one day.

  Oh, did I forget to mention? Yes, the brain-training program is ‘our little secret’. If word gets out that Julie and I are deliberately trying to create smart hydras, we would surely be executed. The generals want obedient killing machines, not dangerous thinkers. But let's not worry about that. What they don't know can't hurt me.

  I've given up on trying to understand Deluge's ‘paintings’. To call them stick figure drawings would be an insult to five-year-old children the world over. Julie says she understands some of it. She believes they're arena fighting scenes. She has a way of getting inside their heads that I sometimes envy.

  Julie recently suggested an interesting method for preventing past disappointments. Considering Deluge's tool use in battle, and with him having survived two activant administrations already, there is a real chance he will be offered (mind->comprehension#1) on his level 10 milestone.

  Our biggest problem now is that there are so many other domains he might be offered as well. If he ignores (mind->comprehension#1) and chooses something constriction-related, I will be very disappointed.

  We need to somehow communicate which domain he should select. Subliminal suggestion, that was Julie's idea. The icons the system uses for domains are the same for all creatures, even monsters. Leaving depictions of our desired choice around his environment leading up to the big match might influence him.

  Well, that is Julie's prediction. She was right about leaving that spear in the arena with the ankylosaur, so I will leave this to her. The big fight is scheduled for tomorrow at noon. We've done everything we can to prepare, but even so, I probably won't be able to sleep tonight.