What if Levi Ackerman had a son that he doesn't know about in the Underground before Erwin made him join the scouts? How would it affect the story? Finished. Enjoy.

After being reborn in a world dominated by colossal walls and dark secrets, Kiyotaka Ackerman, now Mikasa's younger brother, faces his new life with the same cold and calculating demeanor that defined him in the past. While concealing his intellect and superhuman strength, Kiyotaka quietly observes the fragile balance of humanity within the walls, preparing himself to face the destiny that threatens to destroy everything.