General Grievous, once known as Qymaen jai Sheelal, is one of the most iconic characters in the Star Wars universe due to his extensive cybernetic transformation. Originally a Kaleesh warrior from the planet Kalee, his transformation into a cyborg left him with only a few parts of his original body intact. Here’s a detailed look into which parts of General Grievous are still real and how they function within his predominantly mechanical body:

Brain
One of the most crucial parts of General Grievous that remained intact is his brain. The preservation of his brain was essential to retain his personality, memories, and cognitive functions. His brain is encased within his cybernetic head, and it is electronically connected to his new body. This allows Grievous to control his mechanical limbs and body parts with the same ease as he would his organic ones. The brain's preservation was vital to maintaining Grievous' strategic thinking and combat skills, which were highly valued by his Sith masters, Darth Sidious and Count Dooku.

Eyes
Grievous' eyes are another part of his original body that was preserved. His eyes were retained and integrated into his new mechanical head, allowing him to retain his distinctive, menacing glare. These eyes were also modified to interface with his cybernetic systems, enhancing his vision. Grievous could see in both visible and infrared spectrums, giving him an advantage in various combat scenarios. The preservation of his eyes helped maintain some semblance of his original appearance and contributed to his fearsome reputation.

Internal Organs
Certain internal organs of General Grievous were also retained to maintain basic biological functions. Key among these were parts of his lungs and heart. However, these organs were heavily augmented with cybernetics.

Lungs
Grievous’ original organic lungs were replaced with synthetic organs designed to enhance his respiratory capacity. Despite these enhancements, his synthetic lungs were still susceptible to damage, as evidenced by his persistent cough throughout his appearances in the Star Wars saga. This cough is a result of injuries sustained during his transformation and subsequent battles, particularly during his fight with Mace Windu, where he suffered severe damage to his chest. The damaged lungs serve as a reminder of his past and the brutal nature of his transformation.

Heart
Parts of Grievous' heart were also preserved and augmented with cybernetic enhancements. The heart's preservation was necessary to keep his remaining organic tissues alive and functioning. The combination of organic and synthetic components within his cardiovascular system allowed Grievous to maintain a semblance of biological function while significantly increasing his stamina and endurance in combat.

Mechanical Body
The rest of General Grievous' body is entirely mechanical. His limbs, skeletal structure, and various other systems were replaced with advanced cybernetic components. His body is primarily composed of duranium alloy, a type of extremely strong metal alloy commonly used in starships. This material provides Grievous with extraordinary durability and resilience in battle. His mechanical body is designed to enhance his combat abilities, making him a formidable opponent for even the most skilled Jedi.

Limbs
Grievous’ limbs are fully mechanical and highly advanced. They provide him with exceptional strength, speed, and dexterity. His four mechanical arms are capable of wielding multiple lightsabers simultaneously, allowing him to engage in complex and highly effective combat maneuvers. The mechanical design of his limbs also enables him to perform feats of agility and strength far beyond the capabilities of an organic being.

Exoskeleton
Grievous’ exoskeleton is designed to protect his remaining organic components while providing a highly durable and flexible structure for combat. The exoskeleton is equipped with various sensors and combat enhancements, including the ability to generate shields and use advanced targeting systems. This combination of organic and mechanical components makes Grievous a unique and deadly warrior.

Transformation and Aftermath
General Grievous’ transformation from a proud Kaleesh warrior into a cyborg was orchestrated by the Sith, who saw potential in his hatred and combat skills. The process of cybernetic reconstruction was not only physically transformative but also psychologically impactful. The fusion of organic and mechanical parts created a being with enhanced abilities but also a deep sense of loss and anger. Grievous' transformation left him with a desire for revenge against the Jedi and the Republic, which he pursued relentlessly as the Supreme Commander of the Separatist Droid Army.