After forty or so minutes of walking, Henry finally found the source of the mana. It was a huge pyramidical structure made of black blocks of stone, which he recognized as Mephilite. The blocks had strange symbols and magic circles inscribed on them, giving a faint purple glow. The pyramid's top shot a beacon of purple energy into the sky, illuminating the area around it.

"What the hell is this? This much Mephilite in hell must be making copious amounts of mana, and this mana is clearly being used for something here. Let's check it out."

Henry sat down and closed his eyes, activating Mind's Eye to its absolute limit. Ever since he had become a Gun Knight, it had gotten a lot more accurate and precise, so much so that aiming with it was easier than aiming with his actual eyes.

'There's a huge number of demons in here, and it's clear they're pretty strong ones from their mana emissions. This building has five floors in total, and there's a huge mana emission at the top floor. Should I go in?'

You have discovered the dungeon "Demon Knight Mausoleum", where the corpses of dead demonic knights who served in the 72nd to 60th region are stored. Explore the dungeon and defeat the Elite Demon at the top for a large amount of Demon Slaying Energy Exp, as well as other loot. The "Dungeons" menu will also be unlocked.

'Well, there's my answer. Dungeons, eh?'

Henry looked at the huge entrance of the pyramid. There were two Hellswords standing guard, but they hadn't noticed him yet.

'These guys have fire resistance, but with the anti-demonic trait of Demon Slaying Energy, the fire should become a purging flame that can harm them as usual.'

Henry ambushed the two Hellswords, who didn't expect him. They were undead, after all, so they weren't very bright.

They tried to put up a fight, but a quick Cycle of Death finished them off.

'My Demon Slaying Energy really is getting stronger. Back in Andromalia, I couldn't finish these guys off with one hit, even if it was a sword technique form.'

You have slain 2 Mephillian Hellswords. You have gained 390 Demon Slaying Energy Exp. Current: lvl 17, 1390/1700 Exp. You have also gained 40 Darkness Points.

Due to a quest, Hellsword skulls will be automatically collected and added to the inventory.

You have gained 2 Hellsword skulls. Current quest progress: 2/40.

'Oh yeah, I did have a quest to kill 40 Hellswords. Well, I can feel quite a lot of them here, so let's try to finish it.'

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With this, Henry walked into the pyramid.

It was very dark in there, with only the faint light coming from the runes on the wall. Henry concentrated some Demon Slaying Energy on the tip of his sword, causing it glow jade green and act like a torch.

'These circles.... Death, Healing, Fusion, Darkness, and the runes are Hex Tongue. These can only be used to cast one type of magic, that being Necromancy. Could this be some kind of automatic undead production facility? The mana is produced by the Mephilite, which then activates the magic circles carved on the walls, casting Necromancy spells automatically. A mausoleum that revives those buried inside as undead... I don't like it.'

Henry was actually born with a relatively high mana capacity and a sharp mind, so he had once tried to learn magic in his teenage years. After pleading with the head of the orphanage he was raised in for a long time, she finally agreed. He studied a lot and learned many things, but unfortunately, no magic tower or academy would accept an orphan, even though he had passed the entrance exams with flying colors. After all, magic was almost exclusive to the nobles and the wealthy in Severin. In the end, he left the orphanage, joined the army, and had to learn Aura, which meant that at least until he became an Aura King whose Aura was powerful enough to be used in magic, using magic was impossible. However, he still had the basic knowledge he had learned before.

'Well, not like I had hope about becoming an Aura King back then. Now though, who knows?'

He kept walking in the stone halls inside the pyramid, illuminated by his energy, until he found a large room with four sealed coffins inside it. The coffins were three meters tall, so they probably didn't contain humans.

'I feel mana inside each of these, which means there's something living, or at least undead, inside. Shall I take the initiative?'

Henry didn't know whether to open the coffins and ambush what's inside them while it's sleeping, or just leave quietly. In the end, he chose the first choice, as he did need to level up quickly, and he suspected there were Hellswords in here, so he could also gather skulls for the quest.

'Here we go.'

He opened the coffin, and as he thought, it was a slumbering Hellsword. Once he opened the coffin, the Hellsword woke up, but it seemed to still be awakening. Undead didn't sleep, so it was probably magically sealed inside, as a storage of sorts.

Henry took the chance and sliced the Hellsword's burning skull clean off.

You have slain 1 Mephillian Hellsword. You have gained 195 Demon Slaying Energy Exp. Current: lvl 17, 1585/1700 Exp. You have also gained 20 Darkness Points.

That's when he heard an old male voice in his head.

'You may not disrespect the deceased. If you repeat two more times, you will be considered an intruder and punished.'

Note: Slaying demons in the Demon Knight Mausoleum may enrage the will of the Mausoleum and cause the demons inside to rush at you. However, when you trigger this rush, you will receive 50% more Demon Slaying Energy Exp due to the surge of Demonic Energy.

'Ohoh? Well, I like the sound of that. Instead of having to look for them, they'll come to me. How polite. Well, let's "pay respect" to these dead knights, then.'