Frederic uses Sword Guard! Defense raises by 11!
Frederic flips his massive sword, burying the tip in the ground and taking cover behind it. Both you and Karina duck behind him for protection from the slime.

Gram uses Basic Heal on Frederic! Frederic regains 16 HP!
You make sure to use your healing magic on your Tank, bringing him back to very nearly undamaged.

Karina waits!
Karina waits to see what the slime does before she spends any more mana healing.

Large Blue Slime uses Acid Body!
Large Blue Slime uses Flying Press on Frederic!
The now bubbling slime takes another massive leap into the air, bringing down its full might on Frederic. He manages to shift the sword to block the slime somewhat, but he still takes a good shock from the blow, and a lot of the slime deforms around the blade and pushes up against Frederic. There's a loud sizzle, and a grunt of pain from Frederic, before he kicks the back of the sword and knocks the slime back.
Frederic takes 66 damage!
Karina: "FRED! D-don't worry, I can help!"

Karina uses Basic Heal on Frederic! Frederic regains 17 HP!
Karina's healing mitigates the worst of the acid burns, but he's still red all over and bleeding in places.
Frederic: "Gram... Good call. Let's kill this thing before it can do that again."

Link To Character Sheets
Also contains archive of sheets for past rolls.

Frederic uses Crushing Sword and Heavy Slash on the Large Blue Slime!
Gripping his sword, Frederic gives a quick yell as he swings his sword up through the air, and then down into the slime with tremendous strength. It cleaves a wide gap in the body of the slime before impacting the ground hard enough for you to feel it from several feet away. The slime quivers uncertainly, apparently not expecting an attack that could hurt it that much at once.
Large Blue Slime takes 12 damage!

Gram and Karina use Basic Cure on Frederic!
Both you and Karina summon up your magic again, and cast the healing spell on Frederic. This time, the rest of the bleeding stops and most of the redness fades. Karina is visibly relieved, and flashes a quick smile at you.
Frederic regains 16 + 17 HP!

The Large Blue Slime waits!
The slime is still quivering menacingly but also... uncertainly? You're not exactly sure how you're pulling emotions out of a slime's jiggling, but you can sorta of tell that it's frightened. Probably because it's fighting an enemy that not only just survived its strongest attack, but then also dealt a rather significant chunk of damage immediately after.

But this is getting dangerous. You're not sure how many more of those big attacks Frederic can take, and he's your main damage dealer here. It'll take too long to kill this slime the good old fashion way, you need to hit it in the core somehow.
Hm... It seems to be lethargic immediately after it does the giant jumping slam. If you strike right then, you'd have a much better chance of getting a hit in on its weak spot. But you'd need someone besides Frederic to take the hit, or at least to pull the attack and dodge it.
...You don't like where this thought is going.

Link To Character Sheets
Also contains archive of sheets for past rolls.

Just need to keep our rate of healing higher than its rate of damage.

> Karina: Cast Energize on Frederick
> Frederick: Attack the Blue Slime
> Gram: Cast Basic Cure on Frederick

Frederic waits!
Karina casts Energize on Frederic!
Karina renews the strengthening buff on the party tank while Frederic holds back on his attack.
Karina: "There, it's back on! Get him, Fred!"
Frederic: "Get him, eh. Hm. Haven't tried this in a few years, wonder if I've still got it."

Frederic's stabs his sword in the ground and begins stepping towards the slime. You are about to yell in protest, when you see a strange blue shimmer around his arm. Is...
Is that mana?
Frederic uses 9 mana Body Mana Flare on Large Blue Slime!
With the strange, almost wild blue shimmer on his arm, he punches the slime directly. You expect a scream of pain from the slime eating his limb, but... Well, you still got a scream of pain, just not from Frederic.
The slime froths and bubbles as Frederic's fist plunges deep into it, seemingly boiling the slime around the entry wound. That's right, if that's magic, then the slime's body can't absorb the damage!
Large Blue Slime takes 5 phys and 9 mag damage!

Karina: "Woah! I didn't know you could do that!"
Frederic: "Wasn't sure I still could either. It's a stupid move that burns way too much mana, but in a pinch it's useful."

You cheer and heal Frederic again, causing him to give an appreciative nod. He's pretty much entirely restored from that attack he took earlier.
Frederic regains 16 HP!

The slime suddenly lurches, surging again at Frederic, but he easily blocks the attack once more. Seems without the assist from that jump attack, this slime can't get enough momentum to break Frederic's guard. Good.

The slime retreats a bit, clearly distressed. Its wobbles are no longer as strong and confident, but it's still shaking angrily. You see it start bubbling again, raising its acidity for another dangerous attack.

Link To Character Sheets
Also contains archive of sheets for past rolls.

Frederic uses Sword Guard!
Gram waits!
Karina waits!
Frederic takes up a guard position with his sword again, while you and Karina take cover behind him.

The slime lurches up and down once, twice, and then launches into the air again, falling down straight for you while still bubbling angrily.
Large Blue Slime uses Flying Press and Acid Body!
This time because of the damage it's taken, it can't jump as high, and thus has less momentum when it impacts Frederic's guard. Instead of a major blow like before, this time Fred stops it with just a grunt, and pushes it back with a kick to the back of the sword again. It did manage to get some burns in on his arm, but nothing NEAR as major.
Frederic takes 24 damage!

Gram and Karina use Basic Cure on Frederic!
Both you and Karina once more summon up your Basic Heal, restoring Fred's damage. This time the two of you easily repair all the damage he's taken, putting your tank back to peak condition.
Frederic regains 16 + 17 HP!

Frederic: "It's definitely weakening. That blow wasn't nearly as bad as the first. Let's wrap this up."

Link To Character Sheets
Also contains archive of sheets for past rolls.

Frederic stabs his sword into the ground again, and blazes up his arm with Body Mana Flare. Actually, more than just the arm, half his torso and the side of his head too.
...He wouldn't-

Frederic suddenly dashes at the Blue Slime, surprising it for long enough for the knight to reach his enemy and plunge his entire arm into the slime. It shrieks again and starts thrashing, but Frederic has covered every surface contacting the slime with more of the mana aura, burning off any slime that tries to grab on and digest the intruder. Meanwhile, Frederic is groping around inside the slime's body at the core. He makes to grab it several times, but each time the slime shifts just enough to keep the core out of reach. Finally, with a bit of a lunge into it, Frederic manages to wrap his fingers around the core.

Frederic: "Aha! Got you!"
With a victorious yank he extracts the whole slime core rather vigorously, sending a small spray of slime out when he tears his arm loose. The still large mass of blue slime suddenly stops quivering or moving, and just sits there peacefully. Wow, removing the core really works wonders.
Karina: "Nice! We did it! Frederic, that was hard!"
Frederic: "Yes, yes it was. That big blue one was surprisingly tough, but most fights are similarly dangerous."
Karina: "R...really? They're, all going to be like this? This, um, dangerous?"
Frederic: "Honestly, this wasn't even that dangerous. The slime was annoyingly aggravating, but I could've withstood its attacks for quite a while if I really put my back into it."
Karina: ".....Um."

Frederic seems surprisingly satisfied.
Frederic: "Gram, can you help me with the slime? This big one should be all we need for a good payment."
Gram: "Ah, sure."
Together, you bag up the large blue slime in a big canvas sheet and load it aboard the boat. You also make sure to grab the green slime that you bludgeoned to death while you're at it. Still intact, no reason to just leave it behind!

Well, you've got the big slime, and two small slime's worth loaded up. Everyone's feeling a bit drained on mana, and Karina seems to be staring off into space. It's probably a good idea to head back at this point.

Karina: "Huh?! Oh! Uh, yes, yes I'm fine. Just... thinking about stuff. This Adventurer thing is more... serious, than I'd thought. Ehehe..."
Yeah, she's not wrong. All your classes and training don't really prepare you for the reality of monsters trying to, well, EAT you.
Frederic: "All aboard."
Frederic mans the ship's wheel as you and Karina unhook the boat's ropes from the dock, and the ship slowly pull away from the slime island. It takes a long turn around, turning back towards Madosa, and begins the voyage back to town.

> Talk to someone.
> Timeskip

You do, in fact! There's a section in the Adventurer's Guide on the subject! It actually outlines both Magic and Willpower, and the differences between the two.
*Ahem*
Magic and Willpower both function on two basic systems; Mana control and Sequence formation.
Mana control, like it sounds, is the user's ability to control mana in their body, mana being the energy that is converted into magic, which affects the physical world. The core skills of Mana control are to sense it, move it in and out of the body and other objects, and push it through a magic sequence.
Sequence formation has to do with creating a magic sequence, a magic construct made of a small amount of mana that converts the mana pushed into it into physical actions, or sometimes into different magical actions. Being able to form sequences means you can choose how the magic takes shape and what it actually does.
The key difference between Magic and Willpower is which system they work on. Magic and mages work using Mana control, while Willpower and Will practitioners use Sequence formation.

Mages have their spells pre-defined, and after invoking a recorded spell sequence in some way pour their mana into it to cast a spell. They tend to have great control over their output and can cast magic with very specific effects, but their flexibility is low, since they need to spend time "learning" or "acquiring" spells, and can only cast the exact spell that they've learned. Simpler, lower level spells get imprinted upon a mage's soul after a certain amount of practice casting it while something or someone else forms the sequence, or with the help of a few uncommon devices and techniques can be directly imprinted with no practice.

Willpower users on the other hand make their sequences on the fly, crafting a new, unique sequence with each use of their power. After formation, they connect the sequence to themselves and the mana in their body naturally flows into the sequence, "casting" the Will technique. In contrast to mages, they have very poor mana control and generally cannot even move mana in and out of mana stones by themselves. Instead, they can use their powers basically as they see fit. Instead of being restricted to the same spell every time, a Willpower user can vary the shape, size, intensity, duration, and behavior of a move basically automatically. The downside to this is that they are limited to much more basic sequences, without intense training. A mage can just learn a spell with complex behavior once, and can then cast it as much as they want. A Willpower user would have to create that complex behavior from scratch every time they wanted to use it.

You know there are more details to both systems and methodologies of using them, but the Adventurer's Guide is more of a primer than an in-depth textbook, meant to give an overview and basic knowledge of how your party members work their wonders. You'll need to find specialized sources for any deeper info.