I'm a monster in Demon King's Castle

Li Yue was both anxious and eager to see what methods the two mages possessed, so he used Photon Pigment to fade into a shadow and drifted towards the Maze Corridor.

"Your spellcasting just now wasn't clever enough, too flamboyant, and unnecessary..."

As soon as he stepped out, Li Yue heard the young mage lecturing the old mage incessantly; the skeleton squads in the Maze Corridor had already been mostly killed by them, with rubble and broken stones piled all over the ground, and some of the walls were half-scorched.

"Take that Piercing Magic for example, you don't need to unleash the maximum damage of the spell, just use ice magic to slightly restrict their movement first, and then use ice crystals to accurately pierce their soul's dwelling place..." The young mage demonstrated as he spoke, gesturing to freeze the movements of the five remaining skeletons in front of him, and then slightly extending his finger, a few strands of air pierced their soul's dwelling place, causing them to die with a gurgle.

Li Yue observed, suddenly realizing that this young mage seemed to be the leader, invading the Demon King's Castle while also teaching the old mage the essentials of spellcasting...

Clearly, in the world of mages, it's not necessarily the older one who is more powerful.

"Subtle manipulation of magic, understand? Skeletons are a kind of magical creature that looks ferocious, but is actually very fragile." The young mage pointed to the dissipating bones on the ground, "Use your perception magic to pinpoint the unique points on the bones, and specifically grind their souls, which can save magic power..."

The young mage's knowledge and perception were good; he could even sense the skeletons' soul dwelling places.

"Yes, Teacher." The old mage humbly accepted the teaching, "But... as you know, perception has never been my strong suit. After all, I'm only at the sixth rank, not yet reaching the qualitative change of your seventh rank."

"These are not problems, which is why I brought you to the library to search for Brain Spirit Pituitary Glands and create perception-enhancing potions." As the young mage spoke, he cut apart the armor of the joining battle group from a distance, quickly cutting out a pile of iron blocks. "The key is to be flexible in your thinking, not just thinking about destroying everything in front of you."

"This is the Demon King's Castle. First, it's difficult to replenish magic power predictably, so we must conserve it; second, various magical creatures have their own characteristics, so we must never just focus on killing what's in front of us, but see through its essence." The young mage moved his finger slightly, and Li Yue vaguely sensed a mental force near his head, mixing and piling the scattered iron blocks together.

Fitting together seamlessly, these armors no longer posed any threat.

"Since we are the first group to enter the Demon King's Castle, we must maximize our gains. We are mages, not heroes. Do you really want to annihilate all the magical creatures in the Demon King's Castle?" The young mage left a small pile of skeleton soldiers for the old mage to deal with and stood aside.

The old mage also imitated the young mage, using ice magic to freeze the skeletons' movements, chanting spells, slowly marking the soul dwelling places of each skeleton, and then began to "pierce" with his fingers.

Li Yue vaguely sensed that it was a kind of air magic. The damage it inflicted when used by the old mage was not strong, but it was enough to grind away the skeletons' soul dwelling places.

As a result, the originally lively Maze Corridor suddenly became silent. The two mages simply released a little bit of cold air, plus the action of poking the air with their fingers, and calmly solved several skeleton squads.

"I understand. Indeed, this saves a lot of magic power." The old mage took out a magic stone of mediocre quality from his sleeve and held it to replenish his magic power.

"It's good that you understand..." The young mage stared at the scattered bones on the ground, his brow twitching, "You see, this way, we can also preserve the corpses of magical creatures to the greatest extent, and then extract materials..."

Saying that, the young mage finally took out a short magic wand and circled around the dozens of skeletons, chanting incantations; soon, the skeletons gathered together and fused into a huge bone mass.

Seeing this, the old mage took out a test tube, leaned over next to the bone mass, chanted a spell, and waved his magic wand. A strand of bone substance fell from the bone mass into the test tube, slightly suspended.

"Bone crystal, whether it's for making bone wands or magic potions related to bone enhancement... it's a very good material." The young mage said to the old mage, "Only in places like the Demon King's Castle, where skeletons can be constantly nourished by magic, can such materials be nurtured."

"Just like the Brain Spirit Pituitary Gland." The old mage lowered his head slightly, his heart overflowing with respect for the young mage.

After observing for a while, Li Yue also had a general understanding of the two mages' style of behavior, and he was able to glimpse the human attitude towards the Demon King's Castle—besides a few hot-headed heroes, perhaps more humans come to the Demon King's Castle like them?

Calculating gains, treating the Demon King's Castle as a treasure trove, and plundering magic stones and materials to improve themselves?

It seems not much different from what I'm doing.

During the process of the two mages' actions, Li Yue had also been looking for their flaws, but like in the tavern, a faint magical power always floated around the mages, preventing Li Yue's prying and further contact, which should be some kind of guardian magic.

Seventh-rank mage and sixth-rank mage... about the same level as "Octopus Demon Shape" Keli. Li Yue felt that it would be better to wait until they reached his home field before taking action, as he would have a better chance of success.

"Alright, if my divination is correct, the library is ahead, and what we're looking for is there." The young mage waved his magic wand, and the appearance of the library appeared in the air.

But Li Yue recognized that it was the library from the Budibog era, the library without the Bloody Corridor and the Bone Chamber Reception Room, thinking that these two mages should have done their homework and somehow obtained a map of the Demon King's Castle from a certain period.

Just as the map appeared in the air, a huge Brain Spirit Pituitary Gland appeared outside the map—at the exit of the library.

"Huh? Our material... is here?" The young mage was stunned and looked towards where Li Yue was.

Li Yue felt a chill in his heart and retreated decisively, then saw the two mages rushing over like crazy!

"It's here! A Brain Spirit that can hide!" The young mage's eyes suddenly showed fanaticism, his pupils turning blue, as if he had seen through Li Yue's disguise under the "Photon Pigment."

Li Yue shrank back into the Bone Chamber Reception Room, his head still a little dazed—these two mages divined the most valuable pituitary gland, which is himself?

This divination is quite accurate.

The two mages did not delay at all and rushed directly into the Bone Chamber Reception Room, seeing the Brain Spirit retreating rapidly in front of them, and also seeing the surging bone spurs and walls.

【We can't let it escape...】

The two mages had a tacit understanding, and the room suddenly became cold, and the Brain Spirit's movements quickly slowed down.

Immediately afterward, the ubiquitous "Piercing" hit the Brain Spirit, causing its brain to twitch; at the same time as it twitched, the Brain Spirit summoned more Brain Spirits, skeletons, and even slave scholars, and counterattacked the two mages together!

"At this time, we don't need to worry about magic power anymore, because the pituitary gland is our primary goal..." The young mage said, turning his palm over, and several ice spears mixed with air with the "Piercing" attribute instantly wiped out all the magical creatures in the way, even the slave scholars were not spared.

【Humans who associate with demons... magical creatures... it doesn't matter, only magic is the supreme pursuit...】

The young mage revealed his inner thoughts—in the Demon King's Castle, magical creatures are equivalent to prey, and humans do not represent their own kind.

After that, the ice formed a cage, completely blocking the target Brain Spirit's route; the mage waved his staff, and the Brain Spirit was also pulled towards them.

Pierce!

Several holes suddenly appeared on the big brain, brain fluid splattering, merging with the blood of the slave scholars, dissipating like a fart.

"We succeeded!" The old mage clapped his hands and shouted, a gust of wind swept away the corpses of the remaining magical creatures, leaving only the target Brain Spirit in front of him.

The young mage walked forward hesitantly, waved his magic wand, and saw a thick Brain Spirit Pituitary Gland slowly rise, jumping slightly, looking very healthy.

【It seems... something is wrong... too weak... is the Brain Spirit Lord this weak...】

The young mage vaguely felt that there was a problem.