In Mushoku Tensei with an A.I. Chip

"That... was... AWESOME! Go Ghislaine!!!" Eris cheered from the side, while her family members applauded sincerely. She had been awestruck from watching the duel. Never before had she seen Ghislaine go all out like that. And her opponent, though he lost, had also moved faster than her eyes could track. It was awesome!

A fire burned within the girl, inspired to train even harder and reach her instructor's level one day. 

Luna and the rest of Luke's personal guards also applauded in response. Perhaps only Jude and herself had been able to clearly observe the duel. The bunny girl's innate perceptive ability and incredible dynamic vision while the Branded Swordsman's artifically enhanced reaction speed allowed them to catch what happened in the split second as Grant and Ghislaine blurred before reappearing behind each other. 

Sauros chuckled with pride at the result, not out of disrespect, but simply because he was pleased with Ghislaine, their retainer's triumph. 

Hilda and Philip were once more reassured of their family's safety, reminded of Ghislaine's immense strength and position as one of the strongest individuals in the Asura Kingdom.

But at the same time they could not help but look at Luke with a more feverish gaze. Did he just use a healing magic item? They didn't even know such a thing existed. 

Magic items are created through carving or inscribing magic circles onto an item. When mana is channelled into the magic circle, either from the user or from a magic crystal, their effects would be activated. This meant that if the magic circle was designed with the purpose of replicating a Fireball spell, the magic item could thus fire a Fireball. 

However, magic circles for healing spells were extremely rare, and 'legally', only the Millis Church had the authority to draw them. They were also incredibly complicated, requiring a large space to properly and accurately draw. 

Had Anthony somehow managed to condense a healing magic circle onto a magic item? It was news that could rouse the ire of the fiercely protective and possessive Millis Church. 

Naturally, none of them suspected Luke would be the one to have created a magic item capable of healing, and the thought that he was casting these spells chantlessly did not even cross their mind. 

"An incredible performance, miss Ghislaine." Luke inclined his head slightly in acknowledgement. 

"Thank you." Ghislaine looked towards her next opponent, "Then is it your turn now?"

"Do you need to take a break?" Luke offered.

She shook her head, "Not necessary." The benefit of a one strike duel was that the winner would usually not have any injuries or fatigue following the duel unless it was a stalemate and both parties were cut. 

"Very well then." He turned to Grant, "Go get some rest. You can act as the referee for our duel."

"Yes, young master."

As Grant walked out of the arena, Luke used a small amount of magic power to fix the cracked and broken ground left in the wake of their short but intense duel. 

Once more, the Boreas adults were flabbergasted at how many magic items the young man carried with him. First for creating a loud sound when he snapped his fingers, then for healing, presumably another one for protection, and now simply for patching the ground? 

Even the simplest magic items like a magic lantern for creating light would cost upwards of a dozen Asura gold coins. The price rapidly went up for offensive and defensive magic items. Philip didn't even want to calculate how much a healing magic item could sell for. 

Luke and Ghislaine took up their positions. The tension was just as heavy as it had been between the two Sword God practitioners. The expectation from the Sword King was clear–her opponent was not just a 10 year old boy, but a Saint-rank magician well-armed with magic items with unknown effects.

She could not afford to look down on him or underestimate what a magician could do in close range. She unsheathed her sword, and returned to the opening stance of the Longsword of Light. It was, albeit, a predictable first move for Sword God practitioners, but there was a reason why it endured through the centuries. 

As long as she was fast enough, no matter how predictable, it wouldn't matter. 

By contrast, said 10 year old Fire Saint was relaxed. Composed and unperturbed with supreme confidence. His head was held high with the ease of a man five times his elder, self-assured as though having already seen through every possible iteration of what would happen next. 

It was his confidence that led Ghislaine to pull off the eyepatch over her right eye, revealing a green eye that was different from her other brown pupil. The green eye had four lines in the four cardinal directions, making it look like a target reticle of some sort. 

"Hm?" Luke zeroed in on the revealed Demon Eye with great interest. A.I. Chip, scan!

[Scanning anomaly!]

"Could that be…" He breathed out, focusing on Ghislaine's uncovered eye. 

"Yes, it is a Demon Eye." She admitted, though it was not something she had kept hidden for the sake of secrecy in the first place. 

"Fascinating. I have read that some people are born naturally with a demon eye, others through a deal with a demon. I wonder what is the case with yours."

There were only a few obscure references to Demon Eyes in the books Luke had found in the Notos library, and they had been historical texts rather than academic ones. Naturally, he was very curious how they worked. 

"I was born with mine." Ghislaine answered, "It can see magic, so I hope you don't mind me using it for this duel." 

Luke smiled faintly, "Of course. I am honoured you are taking this duel seriously enough to use your Demon Eye. I would like to study your eye if possible, I can pay you."

The Sword King did not take offense to his offer, instead she smirked and proposed a counter-offer, "If you can beat me, you can do as you like."

"Hoh." Luke's smile widened, "Now I actually have an incentive to win."

Ghislaine tilted her head, "Is my young lady's hand not a sufficient prize?"

"It is not a prize, but an obligation." Luke answered with a shrug, angering Eris' parents. 

Hilda tightened the grip on her silk fan, "...an obligation? How discourteous."

"Kick his ass Ghislaine!" Eris yelled out from afar. "I want to see him cry!"

Ghislaine received her young lady's command with an acknowledging nod, "To defend Eris' honour, I shall not hold back." 

"Then, let's begin, shall we?"

"Do you not need your staff?" She asked. 

Luke chuckled, "I'm not used to using a magic conduit like a wand or staff." 

Ghislaine paused for a moment before shrugging, "Very well."

Luke gestured towards Grant, who looked very curious who would be the victor between his young master who stopped losing to him years ago, and the Sword King that just defeated him. 

He cleared his throat and raised up his hand, "On my mark!"

As before, Ghislaine settled into her signature loose but aggressive opening stance for the Longsword of Light. Mana was drawn from her core, transformed into Touki through willpower and fighting spirit, before being layered on her body to reinforce her strength, speed and durability. 

Mana was channelled into her Demon Eye as well to see through any possible telltale undulations of magic that came from the activation of a magic item. Her plan was simple, speed through whatever defensive magic item Luke had ready, and failing that break through it with brute force.

If possible, she would have to control her swing slightly to avoid killing the boy in a single strike. 

[Warning! Subject Touki activated! Threat assessment: High!]

The A.I. Chip immediately fired off a warning to his host at the first sign of Touki reinforcement from the Sword King. 

Said host simply began circulating the mana within his body, the movements of magical energy was not missed by Ghislaine's Magic Power Demon Eye. 

What is he doing? It doesn't seem like he is channeling his mana into any magic items. Ghislaine wondered, but stopped her musing right after. It didn't matter either way. Whatever obstacle placed before her sword and her target would be overcome regardless. 

She refocused back on Luke, already plotting her opening move and the trajectory of her blade. 

"...Begin!" Grant swiped down his hand to declare the start of the duel, and once again a mini explosion saw the ground of the arena cracked from Ghislaine's first step. 

Three steps and 0.15 seconds. That was the A.I. Chip's analysis of how fast it would take for Ghislaine to cross the distance of 15 meters between her and Luke to deliver the first strike. It would take her three steps assuming she used as much Touki as she did when facing Grant, and 0.15 seconds for her Longsword of Light to cut him. 

Luke's natural reaction speed was pretty good. The body of the native he had inhabited had decent talent for martial arts, and the Knight Training Manual, Vajra Pentabolt, he trained in improved the body holistically, so his reaction speed was naturally raised to the level of superhuman. 

For regular humans, or even somewhat trained adventurers, Ghislaine's speed would have been incomprehensible. Literally meaning that they would not even be able to comprehend what just happened until seconds after it had already occurred. 

Even with Luke's enhanced reaction speed, it would have been difficult to react appropriately to such a fast threat. The first step was recognizing visual stimuli. When light enters the eye, the photoreceptors in the retina convert light into electrical signals that then have to be transmitted to the visual cortex in the occipital lobe.

The brain would then have to rapidly interpret the image—identifying the object, its motion, speed, and direction in order to detect danger. 

His brain subsequently would have to track motion, estimating the sword's trajectory and approximate time to impact. Higher-level processing assesses danger, rapidly pulling from memory and experience to evaluate how to respond.

Once a decision has been made on how to deal with the threat, signals would then be sent to the muscles down the spinal cord that then activate specific muscle groups to react to the approaching sword. 

Against someone like Ghislaine who was using the Longsword of Light with a Sword King-level of Touki and technique, no one under Saint-rank can even react before they realized their head was already separated from their body, rolling on the ground. 

If Luke was solely relying on his body's natural reaction speed, he would likely not have been able to respond properly to Ghislaine's Longsword of Light. 

However, for this exchange, he did not have such difficulties. Firstly, Ghislaine's opening move, the Longsword of Light, was a technique that had been observed many times beforehand through Grant's demonstration of it. 

While Ghislaine and Grant executed the signature move of the Sword God school differently, the differences were minute and only affected the A.I. Chip's analysis slightly. 

Furthermore, having seen Ghislaine perform it during her duel with the Sword Saint just minutes before was enough for the A.I. Chip to have already formed a counter measure against the move. 

Ghislaine's expected trajectory, velocity and vector had comprehensively been overlaid on Luke's sight before the battle even began. 

Next, before Grant had called for the duel to commence, Luke had already been circulating his mana. It wasn't done just for fun, obviously. 

While Ghislaine could see the movement of Luke's mana, she would not have realized he had already pre-cast two spells in anticipation for her opening move. That was because she was not a spellcaster; she was expecting Luke to use magic items in their duel; she had never encountered a chantless spellcaster like Luke before. 

Because of all these reasons, the moment when the distance between them was closed, Ghislaine's sword was stopped right before the sword could cut Luke. 

No, the Sword King realized. More accurately, there was a barrier layered right over Luke's clothes that blocked her swing. So this was the magic item the Fire King Anthony had given his disciple!