Shigaraki's decision

 Shigaraki after talking with sue went to rest in his room, he felt severe pain all over his body and his hands kept on vibrating at an abnormal speed."The dark kantar's power is taking too much of a toll on my body, in other to survive i will eventually have to fully give in to the shadow nexus in order for my body to be able to withstand the  power that the dark kantar gives me." he said, as he thought to himself "if i do that, i may not be able to keep my mind intact but if it's for Aoi's sake, i will risk it." He then waited for his body to calm down a little bit and went to sue saying in a very serious tone "it's getting worse, i can barely control my dark chakra usage. It just leaks out of me at random and it's making my body very unstable" he then showed her his left hand which was still vibrating at a very high speed. Sue then said while she opened a black backpack that was beside her as she pointed to a chair next to the wall of the room "sit there, i going to run a few tests." she then used an injection to draw out blood from Shigaraki' s body and placed it in a test tube, after a while of analyzing the blood sample she said in a worried tone "you're right, your body's affinity to the shadow nexus is higher than any of ours so while the rest of our bodies actively try to resist the dark chakra hence reducing its potency, your body accepts the chakra and passively merges it with your own so even when your mark isn't activated, there are still faint traces of the shadow nexuses chakra in you." Shigaraki then looked at Sue with a puzzled face and said in a confused tone "which means?" Sue then smiled and replied "it means that you have to establish a connection with the shadow nexus or the dark chakra in you will be uncontrollable but if you do establish a full connection with the shadow nexus and accept its power, all your chakra would be transformed into dark chakra and if your will isn't strong enough you will be taken over by your negative emotions."   Shigaraki' s face was emotionless as he said "i already knew the consequences,  i came here for you to help me to establish a proper connection to the shadow nexus and gain control over my dark chakra, now do it." Sue with a  worried face then grabbed a silver high tech looking device as she placed it on Shigaraki' s chest and the device became engulfed in dark chakra and the dark chakra proceeded to spread around Shigaraki' s body as his eyes glowed red and his body was emanating a dark aura. Tears began to roll down on Sue's cheeks as she said "The reason why your body has more affinity for the shadow nexus than ours is because your are fueled by your dark emotions, please come back to me Shigaraki."

 In his mind, shigaraki was falling down into a deep pit that was pitch black. It seemed to have no bottom as shigaraki kept falling and falling, the further down he fell the more his emotions of hatred, sadness and betrayal took over him. After what seemed like an eternity, Shigaraki finally reached the bottom of the pit as he landed on his feet and looked around. He saw nothing apart from a giant red gate and upon walking up to it a masked figure appeared in front of him and it said with a voice that sounded like a thunderstorm, "Oh brave one who approaches me, dark one who desires him, only those chosen by him can open these gates and intruders perish by my wrath." it then stepped away to give Shigaraki a chance to open the door and shigaraki seeing this made no hesitation as he went to the door and tried to open it but to his surprise the door didn't budge, he tried again this time putting in more effort but he still couldn't open the door and by the time he had reached his fourth trial the masked figure said "those with light can never hope to obtain the power of darkness, you shall die here!!" it then threw a black lightning bolt at shigaraki which he dodged but right after he had dodged the first attack, the masked figure appeared behind him and used it's hand to stab throw shigaraki's back making a deep wound that made a hole on his body. The pain he felt was immeasurable as he began to cough up blood, he closed his eyes as he thought to himself "I guess I wasn't strong enough to save you Aoi, please forgive me." He was beginning to black out when he heard a malicious voice whisper to him "I knew you were weak, you claim you want to save your friend but in the end after stumbling just once you have decided to give up. If you know you are worthy of my power discard all your emotions of doubt, worry, fear and despair, only by doing that will you be able to harness my power and use it to further your cause." Memories of a younger shigaraki playing with Aoi flooded his mind as a look of determination appeared on his face and he got up saying "I will defeat anyone who stands in my way and bring Aoi back no matter the cost!" He then charged towards the masked figure with speed that made him look like nothing but a blur and landed a clean kick on the masked figure's side which sent him flying a few inches back, the masked figure then looked at shigaraki who's sharingan was glowing bright red and laughed saying "good, try and put up a fight it will make it more satisfying when I destroy you." He then charged towards shigaraki and created a giant black electric dragon without weaving hand signs  and shigaraki on seeing this evolved his sharingan from a three tomoe sharingan to a mongekyo and upon looking at the dragon with his mongekyo, it froze in it's place. He then dashed towards the masked figure as his eyes glowed bright red with the pattern of a stylized broken dragon head with two curved horns, and a serpent like body that wrapped itself around the dragon head making the dragon head to be at the center while the body firmed a circle around it. The masked figure upon seeing the pattern of shigaraki's crimson eyes said to itself "so he is worthy of our power after all" and instead of dodging he stays perfectly still as shigaraki with his arm vibrating at a very high speed stabs through the masked figure's body effectively killing him. 

 After the masked figure died, his body disintegrated into dark chakra particles that integrated themselves into shigaraki's body as the gates Infront of him opened and he heard a voice say a calm voice say "come in, for you have proven yourself worthy he whose eyes bear the markings of kokuryū. A bright light emanated from the open gates and as shigaraki walked through the gates and  he felt a sense of warmth and safety, unknowing to him that he was about to live through his worst memories.