The attack method used by demons is spells, and the energy in their bodies is called spell power, which is different from the magic of wizards.
In their first encounter, Ken couldn't gauge Ares Dreadfall's power fully, so he instinctively hid Mirajane behind him during the confrontation.
"You are a magician who can defeat the entire guild. It seems that the magic power in your bodies is quite high... I wonder what your souls taste like?" Ares Dreadfall said slowly, his withered palms sweeping through the air.
"Rain of Chaos!"
Upon uttering the incantation, Ken and Mirajane suddenly noticed something strange in the sky. The atmosphere trembled, and the scene reminded Ken of Jellal's celestial magic.
Moments later, a series of meteorites with green flames streaked across the sky, heading straight for the guild.
Ken quickly activated the Wings of the Storm Dragon and led Mirajane to dodge carefully.
"Boom!!"
The meteorites crashed, and as the surrounding temperature skyrocketed, bursts of cold air followed.
Ares Dreadfall sneered. "Feel the devil's flames from hell!"
Another spell was cast, and five meteorites that crashed to the ground transformed into massive rock giants, burning with an intense flame. They quickly surrounded Ken and Mirajane.
Ares Dreadfall grinned, eager to watch this massacre unfold.
But Ken, much to Ares Dreadfall's surprise, raised the corners of his mouth.
Within the circle of rock giants, Ken could no longer suppress his inner joy.
"Rocks, flames... now we're talking!" he exclaimed with a grin.
As a Dragon Slayer, no matter how powerful Ares Dreadfall's spells were, they were just food for Ken!
"Attack!" Ares Dreadfall ordered, and the nearest rock giant swung its burning stone arm toward Ken.
Ken quickly shouted, "Mira, find a safe place! I have a way to deal with them!"
"Be safe..." Mirajane trusted Ken and didn't hesitate. As the giant's massive arm came crashing down, she burst into speed and flew out of the area.
"Bang!!"
The giant's attack missed, and it smashed into the ground.
Ken, on the other hand, jumped directly onto the arm of the beast, dodging the attack and landing on it effortlessly. He bent down, opened his mouth, and began chomping down on the rock.
He bit off a large chunk of the green fire-infused rock.
"Quick victory, I'll ride this horse and eat, eat, eat..." Ken muttered.
As the rock giant's body began to disintegrate, the flames on its back began to flicker and fade.
"Ah??" Ares Dreadfall was dumbfounded.
Although Ares Dreadfall was a demon who fed on human spiritual power, he had never encountered this strange fighting style from a Dragon Slayer. He hadn't understood the various fancy magics humans used—this was the first time he saw one devouring magic in such a peculiar way.
Ken, however, didn't slow down. He stuffed the rock giant into his mouth with increasing speed, no time to savor it, only focusing on ending the battle.
As he consumed more of the rock giant, Ken felt subtle changes in his magic power. It felt as though his dragon-slaying power was beginning to mutate.
But the feeling didn't last long, and the desired surge in power never came. Instead, a slight queasiness crept up on him.
"This damn taste... feels like I've been fed a mouthful of history..." Ken muttered with a frown.
He glanced up at the horrified Ares Dreadfall and spoke in a cold, slow tone.
"The devil's flames and stones are so unpalatable that they really make me angry..."
Ares Dreadfall's mind raced in panic.
"I didn't ask you to eat it!" he thought, but fear began to creep in as he realized he was losing control of the situation.
"Crazy... madman! Is he even human!?" Ares Dreadfall shouted in disbelief.
But it was too late for him to complain.
Suddenly, Ken vanished from his spot, and violent thunder and lightning magic crackled around him.
Ken's fists intertwined, and his eyes gleamed with overwhelming power.
"Jaws of the Brontosaurus!" he roared.
Ken's punch hit Ares Dreadfall square on the head, knocking him to the ground with a scream louder than the fat man earlier.
The remaining four rock giants lost control, their flames sputtering out before they crumbled into inert stones.
But Ken sensed something was off. Ares Dreadfall, still lying on the ground and pretending to be dead, still emitted faint magical energy.
"As expected of a demon. You're thick-skinned." Ken muttered.
"But if you don't get up again, I'll punch you in the head again..."
Ares Dreadfall, hearing this, hurriedly sat up, maintaining his distance from Ken. He screamed desperately.
"Behind the Evil Spirit Temple is the Gate of Dark Guild Hades. You can't kill me!"
"The Gate of Hades?" Ken thought, his mind flashing with knowledge.
The Gate of Hades was one of the three most powerful dark guilds, having signed a non-interference pact with the Six Demon Generals and Demon Heart, forming the Balam Alliance.
Ken recalled from the depths of his memory, "The Gate of Hades... It's indeed a tricky thing. But if I remember correctly, they won't take action until seven years from now, right?"
Seeing Ken hesitate, Ares Dreadfall believed he had found an opening and pressed on.
"You've heard of the Gate of Hades, haven't you? There are demons in the Book of Zeref, and the only way to fight against them is to die. Join me in the Evil Spirit Temple, and I will ensure you have an endless supply of magic power to enjoy, just like the hellfire that consumed me..." he tried to tempt Ken.
Ken interrupted him coldly.
"I'm not interested in your hellfire that tastes worse than history."
Ares Dreadfall was taken aback, and a bad feeling rose within him.
Ken then spoke in a chilling tone. "And sooner or later, we'll be taking down the Gate of Hades. It's a pity you won't live to see that day."
"Wait..." Ares Dreadfall's eyes were wide with fear. His dry lips parted, but before he could speak, Ken's iron fist slammed into his face.
Ares Dreadfall's body began to turn transparent before completely vanishing.
"This boss is easier to defeat than the mobs," Ken muttered, wiping his hands.
"Considering the demons, this group wasn't weak... They just had some bad luck. All their spells got eaten by me."