After mastering the absorption of chakra and the vital biological fluids from more than thirty Mist women using his secret Dual Cultivation technique, Uchiha Indra retreated to a hidden chamber beneath Uzumaki Island. Here, isolated and free from all distractions, he began the meticulous process of refining his body at the microscopic level.
Using knowledge from his previous life as a scientist, Indra started focusing on the smallest and most vulnerable parts of muscle and organ anatomy—breaking down old, weak tissue and rebuilding it stronger than ever before with the pure essence he had gathered.
He opened a notebook of anatomical cycles he devised, labeling his upgrade log by stages and cycle order—from the weakest to the strongest body parts.
Upgrade Log — Cycle Order (From Weakest to Strongest)
Stage 1 — Tiny & Fragile Inner Muscles
Stapedius Muscle (controls middle ear vibration)
Tensor Tympani Muscle (ear muscle)
Ciliary Muscle (eye lens focus)
Extraocular Muscles (eye movement)
Auricular Muscles (ear movement)
Palmaris Longus (forearm tendon)
Platysma (thin neck muscle)
Stage 2 — Small but Vital Organs
8. Pineal Gland (regulates circadian rhythm)
9. Pituitary Gland (hormone control center)
10. Hypothalamus
11. Spleen
12. Pancreas
Stage 3 — Small & Weak Bones
13. Stapes (smallest ear bone)
14. Hyoid Bone (neck bone)
15. Floating Ribs (easily fractured ribs)
16. Clavicle (collarbone)
17. Nasal Bone (nose bridge)
18. Coccyx (tailbone)
Stage 4 — Thin Skin Regions
19. Eyelid Skin (very thin and delicate)
20. Lip Skin
21. Ear Lobe Skin
22. Armpit Skin
23. Inner Thigh Skin
Stage 5 — Larger Muscles for Function
24. Masseter (jaw muscle)
25. Sternocleidomastoid (neck rotation)
26. Deltoid (shoulder)
27. Biceps Brachii (upper arm)
28. Triceps Brachii (upper arm)
29. Rectus Abdominis (abdomen)
30. Gluteus Maximus (buttocks)
31. Quadriceps (front thigh)
32. Hamstrings (back thigh)
33. Gastrocnemius (calf)
Stage 6 — Large & Vital Organs
34. Heart
35. Lungs
36. Liver
37. Kidneys
38. Stomach
39. Intestines
Stage 7 — Largest & Strongest Bones
40. Humerus (upper arm bone)
41. Radius (forearm)
42. Ulna (forearm)
43. Femur (thigh bone)
44. Patella (kneecap)
45. Tibia (shin bone)
46. Fibula (calf bone)
47. Spine (cervical, thoracic, lumbar, sacrum)
Each cycle involved delicate destruction at the cellular level, followed by reconstruction infused with pure energy drawn through Dual Cultivation. The process was slow and painstaking; he could only do one cycle at a time, starting from the smallest structures upward.
Indra's concentration deepened as he honed in on the smallest muscle in his body—the Stapedius. Barely larger than a millimeter, this tiny muscle nestled within the middle ear controlled subtle vibrations of the stapes bone, guarding his hearing from damage by loud noises.
With chakra refined to perfection, Indra's inner vision expanded to micro-level anatomy. He saw the stapedius as a classical sickle-shaped muscle—a delicate bundle of fibers stretching from the hollow pyramidal eminence of the temporal bone to the neck of the stapes. Its sickly thin tendon acted like a handle, poised to pull and dampen the bone's movement.
He channeled the essence absorbed from the Mist women deep INTO this tiny muscle, flowing chakra-water along the fibers, filling minute gaps and repairing micro-tears invisible to the naked eye. The muscle, often overlooked and almost forgotten by most shinobi, was critical to his senses—a shield guarding his hearing from the harsh cacophony of battle.
Indra let his chakra gently contract and relax the stapedius, mimicking its protective reflex with precise timing, each contraction measured in milliseconds. The muscle's belly, barely two to three millimeters wide, pulsed under his chakra's nurturing touch. With each pulse, damaged microstructures rebuilt themselves, fibers re-anchoring firmly to the bony attachments.
His control was exquisite—never too rough to tear, never too light to fail. He enhanced the stapedial nerve signals, routed through the facial nerve branches, synchronizing his internal vibration dampening with external sound waves.
In this moment, Indra understood that even such a tiny muscle, often ignored, could be the difference between clarity and chaos. His chakra-woven repair granted him more than endurance—it granted him clarity, allowing him to discern subtle shifts in enemy footsteps or whispered conversations miles away.
He flexed the muscle one last time, feeling it hum softly, an unbreaking shield against the world's chaos.
Satisfied, Indra marked a tick on his upgrade log beside the Stapedius muscle, its strengthening complete—for now.