Help! I'm Trapped Inside Naruto, Playing the Role of His Old Mentor

【Naruto Fanfiction, System Story, Mastermind Behind the Scenes, Character Growth, Making Up for Regrets】 I died right after transmigrating, and got trapped in the Nine-Tails' seal inside Naruto's belly. Talk about a disastrous start! The Nine-Tails was about to go berserk, Naruto was about to turn evil, and we were both done for! At the critical moment, my soul awakened, and I became a mysterious old master! “Young man, do you want to learn real ninjutsu? Do you want everyone who looks down on you to grovel at your feet?” “Take me as your master, and I'll make you the strongest in the shinobi world!” Faced with my tempting offer, a hungry Naruto burst into tears. “Grandpa, I just want a bowl of ramen...” I smiled and conjured a mountain of ramen for him inside the seal! From then on, the shinobi world gained a cunning savior. The Three Basic Jutsu? I used programming concepts to teach him how to master them in a day! The Rasengan? I used fluid mechanics to help him master it in three days! Taijutsu? He could dodge attacks while calculating how much stamina his opponent was using! When Naruto stood on Pain's face and asked him, “How much does a meter of rice weigh?”, the whole shinobi world was stunned! As for me, I stayed hidden in the deepest part of the seal, watching the Naruto world I'd steered toward an entirely new ending, and smiled with satisfaction. “Naruto, it's time to reap the final fruit and restore your master's body!”