The last loot was a legendary-grade runestone. Its name was Runestone of the Devil King.

"It is another of those rare battle runestones,

" Peniel informed.

"Like your Runestone of Spellcasting and Haon's Runestone of Combat, it can help you during combat.

"

"It will give me buff?

" Jack asked.

"It's... a bit complicated,

" Peniel replied.

"If you can master it, you will be stronger with that runestone active. That said, I imagine it will be rather difficult for you to master this runestone.

"

"Huh, why?

" Jack asked.

"Give it a try, and you will understand,

" Peniel answered.

Jack rolled his eyes at his fairy companion. She still had her penchant for withholding information.

Jack thought about trying to fuse with the runestone like Peniel suggested, but he decided to do it later. Fusing with a runestone required time. Since Peniel said fusing with this runestone would be difficult, it should take an even longer time. The war was still ongoing. It would be a waste to throw away all those potential exp points.

"Considering this runestone is already a legendary grade, I no longer need gemstones to upgrade it,

" Jack said.

"Yes. That runestone is already perfect in its basic form,

" Peniel confirmed.

Jack nodded. He stored the runestone before shooting into the sky. He flew at high speed toward the battlefield.

He watched the scene as he approached. The defenders could already fight the underworld force on even grounds when Jack joined the battle. With Satan's demise, the battle tipped further in the defenders' favor. It was only a matter of time until the demons were vanquished.

Jack preferred it to be sooner. They needed to march into Liguritudum as quickly as possible. He looked around for a place with more enemies. After locating the spot, he dashed over.

"Time to test your power!

" Jack exclaimed. He used the Void Demon Sword.

When the sword appeared, he was taken aback. The reason was the sword's size. He thought it would be a normal-sized sword, or at most, the size of a greatsword. However, the sword that appeared was freaking huge. It was the size of a small ship. It was probably a hundred meters in length.

The sword was composed of voids. When one looked at its surface, one could almost gleam a different world behind that void. The gigantic sword rushed forward when Jack was still processing its appearance.

With its gigantic mass, it swept through many demons at once. With one sweep, many were killed. Some were because their HP was already low. Another portion was because they received the instant-death effect. The remaining were due to suffering fatal wounds, like having their heads decapitated. Half of those who survived suffered wounds that weakened their fighting abilities and reduced their max HP.

The Void Demon Sword was not slow. It was also sentient. It detected nearby enemies and zoomed over, cutting many demons as it slashed past. The demons tried to move away when they saw this giant flying sword come over, but the slow ones found their bodies becoming heavy when the sword approached. They also received small damage every second. They were helpless as the void sword sliced into them.

Some tried using attacks to break the sword. However, all their attacks were as if sinking into a bottomless abyss. No apparent damage was visible on the sword. To make matters worse, several small swords started flying out from inside the void of the giant sword. These small swords spread out and struck the demons not in the giant sword's trajectory.

The demons had no means to destroy the Void Demon Sword. Defensive skills or spells still worked in reducing the damage they received. But since the Void Demon Sword had an instant-death effect and had a high chance of wounding, those defensive abilities were largely ineffective. The best move to deal with this void sword was not getting hit, but the demonic field it exuded rendered even that difficult.

In a short time, the demons' formation at the place where Jack was was a total mess. Jack hadn't even done anything else after conjuring the Void Demon Sword. The demons were too busy dealing with the void sword to do anything to Jack, who just floated above them.

One unfortunate thing was that this void sword dealt friendly fire. If allies were in the sword's path, they suffered damage too. The sword was sentient and tried to avoid allies. But with its bulky build, collateral damage was bound to happen sooner or later.

Jack had chosen an area where more enemies were grouped. But with how chaotic the battlefield was, some allies were there as well.

At one unfortunate instant, an ally was cut by the void sword together with the demons. The worst thing happened. The wounding effect triggered. That ally's body was cut in two, and he died instantly.

"Oh, **!

" Jack exclaimed. Even though it was unintentional, he still felt a grave guilt seeing the scene.

The killed ally was a strong combatant, a level 85 mythical grade from the Council of Elpo. Losing such a combatant was a great loss.

"Your new spell!

" Peniel reminded Jack. She sensed the guilty feeling within Jack's heart.

"Right!

" Jack remembered. He hurriedly cast Time Reverse.

The Time Reverse turned back time by one minute. The spell was a nine-rune spell, but the runes composing the spell formation were not too intricate. This let Jack cast the spell

quickly.

After casting the spell, time started to flow backward. He saw himself and everything around him move back in time as if watching a rewinding video. It was the same sensation as the time when he was doing the trial for the Time Sage.

As he saw everything moving back in time, his mana manipulation informed him that he could exert control over the process and stop it if he wanted. This meant he didn't need to go all the way back to one minute before he cast the spell.

He tested doing that and stopped the process. Unfortunately, he learned that even if he stopped the process midway, the cooldown was still a full hour. He stopped the time reverse just a few seconds before the unfortunate ally was killed by his void sword. He used Wind Dash and zoomed toward the ally.

The ally was startled when Jack suddenly appeared before him. Jack grabbed him and used the second dash to pull him away. The ally was dazed by Jack's interference, but he soon noticed the void sword charging past where he used to be. He had been so absorbed in the battle that he failed to sense the incoming sword. He understood then why Jack pulled him away.

"Tha... Thank you...,

" he stammered.

Jack gave him a friendly tap.

"Leave this place to me. You go help the others,

" Jack told him. The ally didn't disagree. He went away.

Jack returned his attention to the void sword still causing havoc among the demons. His Time Reverse had a one-hour cooldown. If the same incident happened again before the cooldown ended, he wouldn't be able to undo it.

"Hm... Let's see if I can control it,

" Jack uttered.

He used mana manipulation to strengthen the connection between him and the void sword. Once the link became clear, he knew he could influence the sword. He controlled it to go after the higher-grade and higher-level demons. He also empowered it, making it deal more damage and move faster. His current level of mana manipulation was advanced enough for him to do this, even when this was his first time using the skill.

Under his control, Jack made the void sword perform sword arts. He couldn't perform Formless Flowing Sword Style. That art needed at least two swords, but he could perform One-word Slash and One-word Thrust.

When he performed those sword arts, a void line was created following the slash or thrust. This void line lingered for several seconds. Demons who touched this void line received damage. Additionally, using the sword arts seemed to increase its instant-death and wounding effects. The rate at which the demons died increased.

Although the Void Demon Sword lasted only three minutes, it left a long trail of dead demons

after it ended.

"Hehe. That was one deadly skill,

" Jack remarked.

"You must thank the demonic seed. The original Void Living Sword isn't that big and fast,

"

Peniel informed.

The surviving demons turned to Jack. If it was before, they would have looked at Jack in fury accompanied by the desire to tear Jack apart, but they were under the debuffing effects after losing Satan. What their eyes expressed was fear and anxiety. They couldn't bring themselves to retaliate. They just stood there with dreadful stares, until one of the stronger demons

uttered a rallying cry.

"What are you all doing? We are the mighty force of the underworld. Attacckkk...!!!

"

Not all the demons acted, but enough did. They sent ranged attacks before they charged forward. Jack didn't worry. He looked at the incoming attacks with a smile. The Runic Ring of Defense appeared before him. He used mana manipulation to empower the ring. The ring spun and flared brightly due to the injection of mana.

All the incoming attacks were blocked by the ring. Jack received no damage. There was also no visible crack on it. The ring was more durable than he expected.

Jack used another new skill, Devil Eye Flare. Two fiery beams shot out from his eyes. The two beams sneaked through the horde of incoming demons and struck the demon who had uttered the rallying cry. The other demons who were late in reacting felt demoralized seeing that. They paused from joining the attack.

Jack then used Devil Blood, the active skill from the Ring of Devil Incarnate. Crimson blood vessels bulged through the draconic scales of his Supreme Dragon Form. Thin crimson mist sipped out of those blood vessels.

After that, a dark purple bubble encapsulated him. It was the Sphere of Tiamat, which had just gone off cooldown. With the boosts from the sphere and the Devil Blood, Jack charged toward

the incoming demons.