Why doesn't the Byakugan have a second stage?


The Uchiha Clan had the Sharingan which has a lot of different stages:

  * Sharingan (Increases power with age/3 commas = maturity)
  * Mangekyo Sharingan (Unlock = Kill a close friend/family member) (Blindness over time)
  * Time Erase (Kasashi's Mangekyo Sharingan)
  * Eternal Mangekyo Sharingan (Perfect vision/Incredible Power)
  * Amaterasu (Invincible Fire Attack)
  * Tsukuyomi (Illusion Technique)
  * Mind Control (Shisui Uchiha 'Mental Genjustu')
  * Copying Ability (Endless library of techniques) (See opponents techniques/Mimic opponent)
  * Susano'o (Giant Skeleton/Invincible Sword 'Totsuka Blade'/Invincible Shield 'Yata Mirror')
  * The Blade and Mirror were found by Itachi, by unknown means - Teleportation
  * Intangibility (Madara Uchiha)
  * Izanagi (Dream/Illusion Technique)
  * Sharingan+Rinnegan Techniques
  * Mangekyo/Eternal Mangekyo 

And it varies for each user in shape and appearances:

  * Sasuke Uchiha - Six-Sided Star Shape (Mangekyo) Six-Sided Cyclone (Eternal)
  * Itachi Uchiha - Three-Sided Cyclone
  * Kakashi Hatake - Bizarre Three-Sided and Curved Cyclone
  * Madara Uchiha - Izuna Uchiha - Stange Opened Circle with Three Squarish-Openings
  * Shisui Uchiha - Four Sided Throwing Star

But the Byakugan stays the same and every member has the same one.

So it makes me curious, why doesn't Byakugan have a second stage?




There is a "second stage" of the Byakugan, called
[**Tenseigan**](http://naruto.wikia.com/wiki/Tenseigan). And it has its own
Chakra Mode, which is said to be on par with the Naruto's Nine-Tails Chakra
Mode.

When the Byakugan is combined with the chakra of an Ōtsutsuki clan member, it
evolves into the Tenseigan. The only known wielders are:

  * Hamura Ōtsutsuki
  * Toneri Ōtsutsuki

![enter image description here](https://i.stack.imgur.com/RcOuK.png)

The Tenseigan has abilities similar to the Rinnegan.

> The Tenseigan allows the user to control both attractive and repulsive
> forces, similar to the Rinnegan. Additionally, it also grants the wielder
> Tenseigan Chakra Mode, which in turn gives the user an increase in speed,
> power, strength, durability, and reflexes. It also grants its user Truth-
> Seeking Balls, thus granting the user all five nature transformations and
> Yin–Yang Release.
>
> source: [Naruto Wikia](http://naruto.wikia.com/wiki/Tenseigan)

