Why are so many Sith cyborgs?

Question

I notice that many of the Sith have some form of mechanical support: not just Darth Vader, but also Malgus, Plagueis and Malak. While this may well just be a trope (Ooh! Bad person! Bit cyborg-y!), I'd be interested to know if there are any other reasons why what appears to be a high proportion of the Sith suffer injury requring mechanical replacement. I can see 2 possibilities:

• Being a Sith Lord is a high-risk occupation (more so than for Jedi) and serious injury is much more likely.
• While serious injury is likely for both Jedi and Sith, Sith techniques are better able to survive

Is there anything in (or out of) canon which would shed light on this?

Answer 1

The Dark Side doesn't have more cyborgs

I am going to have to disagree with the reasoning that they become more robotic because they use the Dark Side and that it somehow corrupts their cells. While it is certainly true that the Dark Side corrupts, there is no reason to assume that this is why they all end up as cyborgs, there are plenty of Sith in the continuity that aren't cyborgs.

Light Side Cyborgs

What happens when Luke's arm gets cut off? Normal healing doesn't allow you to regrow an arm, so they replace it with a prosthetic that looks as human as possible. But Sith are fighters and warriors, when they lose a limb, their first thought is not 'how can I make the replacement look as natural as possible?', they're far more likely to go 'how can I make this replacement as lethal as possible for my foes?'

Light Side users and the general populace are all about trying to blend in, they don't want to stand out. But a Sith is all about individualism. They don't mind if their new arm is bulky and scary looking, as long as it works well. If people are threatened by it, all the better.

Why do Dark Side users lose so many limbs?

Worth noting is that Jedi don't generally fight other lightsaber users, they fight against people who use blasters. If a blaster shot doesn't kill you, you can get healed and you don't really need any replacement bodyparts.

Sith on the other hand constantly fight lightsaber wielding opponents, either each other or Jedi. This leaves far more chance for losing limbs, and thus needing replacements.

Answer 2

In recognition of Null's justified criticism I will say that while my answer provides a good explanation of the physical degradation advanced dark-side force users experience, as well as an explanation for a limited number of cases where Sith have been forced to become at least partly robotic, it is perhaps only one component of the answer OP is seeking since it does not directly address the cases of the Sith he specifically cited.

The dark side energies that the Sith channel are actually physically harmful to living bodies - the biological form of a Sith Lord tends to wither over time, especially as they grow more powerful. For reference see this article on Wookieepedia, specifically the section titled "Corruption of the Dark Side" where it is stated:

"The dark side, much like a strong, addictive narcotic, affected not only the mind of the user but the appearance as well. As one immersed oneself deeper within the dark side of the Force, its malevolent power took a toll on the body...because flesh and bone lacked the endurance to channel the immense power of the dark side indefinitely."

This is in direct contrast to the light side energies channeled by the Jedi, which are specifically tuned for the preservation and augmentation of life.

As an example consider what is perhaps the the ultimate expression of Sideous' force abilities in the films: lightning. The energy that he conjures is incredibly frightening and powerful and has absolutely no practical application aside from destruction. This energy is literally coursing through Sideous' body at every moment, and the "current" has weathered his physically-human form terribly over time.

Compare this example of dark side energy to the light side of the force and you will see that there is obviously no real equivalent. The dangerous energies that flow through a Sith Lord's body are not present in a Jedi, and it is because of this that light-side force practitioners do not suffer the physical ailments and disfigurements so common to the Sith, including their need for mechanical replacements for failing organic systems. From the same article linked to above:

In time, the corruption could go beyond mere cosmetic details and directly impair physical abilities. King Ommin of Onderon was a proficient Sith sorcerer for most of his life, and the dark side held him under its decaying influence until he eventually became incapable of movement and needed support from a cyborg exoskeleton in order to survive. Another extreme case of dark side corruption was Darth Zash, whose extensive study of the dark side led to immense physical degradation and eventually a fatal terminal condition. The worst case of this transformation would be Darth Nihilus, who was completely consumed by the dark side both mentally and physically. Eventually, he became an aberration of the dark side that existed only to consume life.

Answer 3

Dark side corrupts. So the cels in the body degrade and the dark side users cant regenerate new cells like a "normal" person. So when a Sith suffers a major injury the best way of getting on is to go full android.

It is a bit different for light side users. Light side focuses more on protection an healing. So the same injury suffered by a light side user would get treated differently.

Put a person in a bacta tank/ get a jedi healer to work on them.

The added bonus in the end is that evil gets more evil-y as you put it by adding a lot of metal parts or whatnot to a body.