Chesu at least had the decency to look embarrassed. Once again that arm was slung behind his head, and he seemed to be scratching at his neck. “Well, see, kid, those carrots? Sort of a problem.”

Gem sent him an image of a nonplussed gem.

“As a Dungeon Core, you don’t natively have much adventurers want. They can’t interact with your blocks—regardless, why would they want them?—and you can’t give them your mobs. Other than that… you need to absorb things to have access to them.”

“Er… adventurers need to drop them while within your area of influence.”

Had Gem a nose, he would have rubbed the bridge of it in frustration.

“There is one other way.” Chesu grinned. “Have you been creating extra Mobs Hearts while you build?”

Chesu snapped his fingers. “Darn. Well, alright. We’ve still got some time and I assume you aren’t actively burning your mana right now to make those blocks.”

Gem checked.

“Oh, perfect!” The wisp’s face lit up. “Let’s make about twenty unaligned Hearts. But don’t summon mobs or make Pylons with them; we’re going to do something else.”

Gem followed the wisp’s advice and made twenty unaligned Hearts. It was faster going than his first attempts, but the motes of mana were still unwieldy things that wanted to do whatever they wanted. He placed each one on the floor beneath Chesu’s floating feet, not even bothering to lay them out nicely. Each Heart clanked with a hollow noise as it fell to join the others.

When all twenty were done, Gem felt like he had a bit of a headache. Which wasn’t quite right, since he didn’t have a head, but it was the same feeling. It pulsed to some unknown beat and made his thoughts swim aimlessly.

He asked Chesu about it and the wisp frowned. “Working with mana is working with the basic elements of the world. It drains you. Even if you aren’t out of mana, it’s still a form of mana sickness. If we weren’t on such a tight turn around, I’d tell you to rest. But if you fall asleep, it could be weeks before you’re up and we don’t have that sort of time.”

Gem sent the wisp an image of a multifaceted gem with a weary expression.

Chesu looked at the unaligned Hearts on the ground. “Let this be a lesson though kid; building is great but you need to keep up on progression. Always have about twenty Hearts lying around. You’ll want them as backups to store your mob's personalities when they die, and you also don’t want to have to craft them between level ups. Just have a stockpile and you’ll be fine.”

Gem thought, adding making Hearts to his never-ending list of things to do with his free time.

“Adventurers are, generally speaking, pretty stupid.” The wisp flashed a wide grin. “They don’t know if an unaligned Heart is full of treasure, or, perhaps, if it’s full of something like, oh, let’s say lava. If it’s an empty Heart, they’ll just take it and try to sell it. But a Heart that has something inside? You break it when they touch it so they get the goods. And if it’s, again, full of lava…”

Gem laughed.

“Eventually you can fill the Hearts with actual things that adventurers want. That whole dungeon theory balance thing. But you don’t have to.”

Chesu agreed with a quick nod. “Lava won’t instantly kill an adventurer. Especially not one above Tin 4 or so. It’ll just be enough to make them cautious.”

Gem grew sullen.

Chesu tapped his chin thoughtfully. “What if you just made more trap rooms? And only allow certain ones to be available for each run?”

“Replace the doors with blocks. It isn’t a perfect solution, and traps eventually stop becoming useful for experience gain. But it could keep some of that mystique going.”

Gem thought about it for a moment before nodding. He added the task to his mental list.

“Smart thinking, kid!”

Gem felt a bit of warmth spread through his core. Instead of basking in the feeling, he looked to the pile of unaligned Hearts.

“Yeah. Go ahead and populate, and pick which doors you’re going to close.”

Gem wanted to point out that if he were only putting one in each room, he didn’t need to make so many Hearts. But he surmised that Chesu actually had him make them all so he’d have extra on hand. He did have mobs to place after this.

He didn’t wait for the wisp to respond. Gem collected the Hearts in his inventory and then moved his attention down into the dungeon. He removed the door on the lava room and replaced it with stone blocks. After some thought, he also did that for the Plantlings’s room. While he was really proud of it, he wanted the Plantlings to be a surprise, not an expectation.

After the walls were closed off, Gem focused on filling the unaligned Hearts with lava. He expected it to be some sort of tricky process, but as soon as he examined a Heart with a bucket of lava in his inventory, the option to Combine sprang to life.

He wished he had something to fill them with other than another trick, but it would have to do for now.

Upon filling the hearts with lava they doubled in size. When Gem examined them, they were tagged with “unaligned Heart - filled {{lava}},” and he assumed that the last bit would be left off the tag if an adventurer looked at them.

The five lava-filled Hearts were placed in each room, even the ones that were closed off. Gem didn’t want to have to mess with anything to reorient them. He then created a mathematical rotation of thirty-two layouts, where each room was represented by an on or off configuration. During the first rotation, all doors would be closed. And during the thirty-second, all doors would be open.

He would just need to choose a rotation from between zero and thirty-one, at least until he added more doors and then things became more complicated.

Currently, his rooms were in the thirteenth rotation, since doors two and five were closed.

It made sense to him, but trying to explain the idea to Chesu just left the wisp scratching his head. “I don’t get it,” he complained the first time, so Gem tried to explain it a second way using saplings as an example instead of doors. They weren’t open and closed, they were saplings and trees.

But that didn’t seem to help the wisp any, either.

“Listen, kid. Mathematics and I aren’t exactly friends. So you go ahead and keep all that in your head—er, gem—and if it works it works.” The wisp waved a hand through the air as if to dispel Gem’s unspoken arguments. “We don’t have time to sit here and teach an old wisp new math.”

Time was something they definitely didn’t have, so Gem didn’t argue further. He still firmly believed the concept and mathematics weren’t too difficult, but every second spent discussing was one the Ostrum would be closer to destroying the World Core.

Chesu rubbed his hands together greedily. “Excellent. My favorite part. I’m really excited to see the mobs you have other than the Plantlings.” The wisp shuddered. “They’re kinda creepy.”

“Oh, just you wait, kid. That’s absolutely a possibility and one you need some experience points for, so let’s go already!”