Body enhancement, also known as Bio-enhancement, is a technique to enhance a person's abilities, mainly strength, endurance and lifespan, but can also be tailored for specific goals.
In the advanced technological societies in the Galaxy, body enhancement is a common practice to improve yourself and is the leading reason so many of the advanced races, even non-Juraians, have such long lifespans and tremendous abilities. That is not to say that Juraians do not practice body enhancement. In the novel, True Tenchi Muyo! Volume 3: Washu, which mainly takes place 20,000 years before the events of the main timeline, it is revealed that even then Jurai had succeeded in body enhancement techniques that far surpassed those of the rest of the galaxy. Even non-royal Juraians are known for their superior strength and combat prowess thanks to their advancements.
Body Enhancement involves using nanotech to alter the individual's genetics and physiology. According to Kiriko, while invisible to the untrained eye, even Earth's medical technology could detect the alterations.
There are levels of enhancements that can be done that can be specialized for certain purposes.
In Tenchi Muyo! GXP, when Seina Yamada receives his first body enhancement, it is explained that his lifespan has been extended to at least 2000 years, and further enhancements could greatly increase that (although through his association with his royal tree and mainly due to the wishes of Tenchi, he is effectively immortal). Characters like Airi Masaki, Kanemitsu Hirata, and Seiryo Tennan, all of whom are not members of Juraian Royalty (who receive life-sustaining energy from their Royal Trees) or descended from the likes of Washu, owe their longevity and special skills largely to body enhancement.
At one point in the GXP novels, Washu inspects the body enhancements of Hakuren, Gyokuren, Karen, and Suiren and further illuminates some aspects of enhancement. Hakuren has level six enhancement but has an emphasis on thought acceleration in order to be a better tactician. Gyokuren is level 6 and Karen is level 5, with no special focus, but make up for that with their natural abilities and training. Suiren was set at level ten, the highest level possible and it is explained that such a level is dangerous. At level ten, a person's body is so thoroughly protected from the environment and becomes rather detached from their mind that others find it hard to perceive their presence and in the worst scenario, the body's astral (soul) is lost and the person becomes a hollow shell and cannot even be considered a intelligent being. Suiren was already suffering from the symptoms of this issue when Washu met her, so Washu adjusted her enhancements, functionally lowering her level and letting her live a more complete life. Being enhanced to such a level could allow a person to better integrate with technology, but outside means, such as specialized Guardian Systems, can do so more effectively. It is unknown why this was done to her originally.
We are never told explicitly what each level of bio-enhancement does, but we have been given some information:
- At enhancement level 1, Seina's physical abilities are augmented to the point where he can throw himself across a large room from the effort that could normally just cause him to take a single step. It also increases his lifespan to roughly 2,000 years.
- At enhancement level 3, the GXP novels state that Seina's senses have increased enormously, to the point he sometimes finds himself accidentally seeing through clothing.
- At enhancement level 10, such as Suiren, it causes dangerous side effects, running the risk of destroying their mind and soul.