~Flashback~
"Yuuki, why did you save me back then?"
A few days have passed ever since Yuuki had saved her. Truth be told, Rui couldn't get the boy out of her mind. She kept wondering why the boy had saved her. After hearing about him through rumors from the other orphans in the project, she decided to confront him.
"No reason."
"E-eh."
"I didn't save you out of the kindness of my heart. I'm not a saint or some hero. But......."
"You're an amazing person...Yuuki!"
"If I let you die....I wouldn't be able to look my friend in the eyes again."
It was only one moment. For an instant, Rui could've sworn that she sadness in Yuuki's empty eyes. A person so strong, yet so vulnerable at the same time. It was this type of person that saved her. As she clenched her fists, she stood up as she pointed at Yuuki.
"Listen up, i'll grow stronger. In this place, we don't have time to worry about anything else, right? Just you watch, i'll grow so strong that you won't need to worry about me. I promise you that!"
".......you're really bad at comforting people. You make it sound like you hate me for saving you."
"W-wait. Did I really come off like that?!"
As Rui said this, she turned around as her face was a bright red as she used her hands to cover it. Meanwhile, she heard a small chuckle escape from Yuuki's lips.
"Though, I think i'm starting to take a liking to you. What's your name?"
"R-Rui...Rui Hachiouji."
"Well then Rui, let's both get stronger."
~Flashback ends~
"Zan-ei!!!"
The moment Yuuki jumped in the air, he quickly used his sound to propel him forward as he noticed something. The shadow of the building behind was cut. Shortly afterwards, the building was sliced in a clean cut just like the shadow.
"Zan-Ei, the Slashing Shadow, it lets Rui slash apart shadows. Not only that, the victim and its shadow mirror each other. Any damage done to it will be dealt to the owner. I'm fast enough to dodge her attacks, that's why she used a surprise attack when she first arrived. That was the only way to attack me with Zan-Ei.....but I can't save her just by being defensive."
As Yuuki thought to himself, he lands on the ground as he was dashing towards Rui with incredible speed. He needs to end this quickly and go after Hitomi. However, if he gets to serious, he might end up killing Rui.
"Sound Domination:Sonic Sew!"
Yuuki surrounded his right hand with sound waves as he was about to strike at Rui. However, his eyes widen in shock with what happened next. The shadows of the buildings around him gathered around Rui as it formed a wall in front of her. As Yuuki's attack connected with Rui's defense. He couldn't believe his eyes.
"Nothing?! Sonic Sew didn't even make a crack in it!!"
While Yuuki was in shock, he screamed in pain as he felt a stinging sensation in his left arm. When he looked downwards, he saw a sharpened tendril has formed from his own shadow. As Yuuki jumped high in the air, he screamed in pain as moving his body upwards helped remove the tendril. While he was up in the air, he saw Rui was still inside of the wall of shadows.
"Let's see how strong that defense of yours really is. Sound Domination:Machine Gun Voice!!!!"
Using a staccato shout, Yuuki fired multiple "bullets" of sound towards Rui's wall of shadows. Yuuki mentally smirked as he saw one thing upon that ironclad defense, a small scratch. He knew what he had to do.
"Instead of trying to destroy the wall completely....i'll destroy a single area and break through!!!"
"Sound Domination:Voice Cutter!!!!"
Through using high frequency vibrations from his sound, Yuuki launched several thin "blades" of sound towards Rui's wall. Soon a small crack was beginning to form as Yuuki's attack connected. Before he could react, Yuuki hissed in pain. A wolf that was pitch black was emerging from his own shadow as it bit his right leg. Using his left leg, Yuuki kicked the wolf as he quickly jumped in the air and moved around using the bursts of sound to propel himself.
"If I stay on the ground too long, Rui creates objects from my own shadow to attack me. If I stay in the air for too long......"
Yuuki suddenly flew to the left as several tendrils emerge from the shadows and try to skewer him. While this happened, Yuuki was trying to think of what to do next. He already formed a crack in Rui's defense. All he needed now was a powerful attack to shatter it.
"Sorry, Rui. Sound Domination:Thunder Noise!!!!"
Yuuki shouts upward into the air, where a "cloud" of sound forms. The sound echoes and condenses within the cloud, becoming louder and more intense, before falling from the sky as thunderbolt-like blasts of sound. As the attack crashed down onto Rui's defense, Yuuki lands on the ground as he saw Rui's wall of shadow shattering while the ground cracked from the intensity of his attack.
Yet this didn't help Yuuki feel like he had the advantage. It was the opposite if he were to be honest. For Rui to let him destroy her defense while fighting back so minimally, it felt like he walked into a trap.
"Yuuki...we Code Breakers have grown stronger over the years. Naturally that would mean i've found a way to further my strength. Going by how you're fighting....it would seem i'm the superior one in this moment."
As Rui spoke, Yuuki couldn't help but clench his fists. Her voice was as cold as ice. It held no type of emotion in it. This wasn't anything like the Rui he knew. Soon Yuuki looked at Rui in shock as he saw what was happening to her.
"The shadows around her....are they merging with her?"
"It is over, Scarlet Demon Yuuki."
"Heh. Hahahahahahah!"
"What is so funny?"
"It's just, i'm happy you've gotten stronger and that you're giving it your all. It means I don't have to restrain myself as much. However, one thing you said rubbed me the wrong way."
The moment Yuuki said this, he vanished from Rui's sight. Before she knew it, Rui felt a kick to her stomach as she was sent flying backwards. When she stood back up, she saw Yuuki staring her down as he cracked his fists.
"You said that you were superior. You believe you are stronger? Fine then, it seems I need to teach you why i'm ranked higher than you."