Saiyans are a warrior race!
That was a handy miscalculation
|Color|| (Gohan, Goku, Shaun, and Kayla)|
|Similar techniques||Nightmare's Awakening|
"Around and around he goes...working his body and chi almost to death and then refreshing himself by eating the Senzu... Whether he realizes it or not, Goku is living and reliving one of the primal cycles of the Saiyans... Gaining strength by facing and overcoming death!"
During the Namek and Frieza Sagas, Zenkai is an extremely important element of the series, which allows Goku and Vegeta's powers to increase in order to "catch up" to Frieza and his men. However, Zenkai are abandoned (or at least go unmentioned) after the Frieza Saga, but return for one single instance in the Cell arc when Cell returns from his botched self-destruction on King Kai's planet, his power amplified to the point that he has high enough amounts of energy surrounding his body to mimic the style of aura that a Super Saiyan 2 has.
Outside the anime/manga series, Zenkai was also mentioned in the movie Dragon Ball Z: Broly - The Legendary Super Saiyan (it was stated that Broly survived his execution and grew stronger due to his Saiyan genes), as well as Dragon Ball Z: Broly - Second Coming (it was implied that Broly grew significantly stronger while in a coma for seven years after being beaten by Goku and recovering).
For example, when Vegeta recovers from his first fight with Goku, his power level went from 18,000 to 24,000, and another was received after being nearly killed by Zarbon's transformed state and healed in a Medical Machine, which the Daizenshuu estimates to have augumented his strength to roughly 30,000. After Vegeta was again near-fatally injured after fighting Recoome, his strength strangely skyrockets enough to have an even power struggle with Frieza's first form (stated to be 530,000), and another, final Zenkai increased his power enough to see Frieza's movements and Death Beams at first, before he begins to put in even more effort. While the dub incorrectly implies that Zenkais only occur with Elite Saiyans, Goku, whom Vegeta and Nappa repeatedly refer to as low-level trash ("clown" in the dubbed anime), receives them many times. This is confirmed by how Krillin states that it was weird how Goku always seemed to grow ever stronger after recovering from fighting devastating battles against powerful foes, how Goku is able to learn and tap into the power of Zenkai's during his gravity training (which in total boosted his power from "over 8,000" to 90,000 in the Namek saga, as 180,000/2 = 90,000), and how Goku's powers again receive an enormous boost after recovering from his battle with Captain Ginyu in the rejuvenation chamber.
The primary drawback from the Saiyan Power boost appears to be its lack of consistency. Although a saiyan is supposed to become "more powerful" after recovering from an injury, exactly how much power that is gained appears to be random and arbitrary, in stark contrast to other power boosts such as Kaio-Ken or Super Saiyan, which always boost the users' power in a consistent, set multiplier. This is best displayed during the fight against Frieza. At the beginning of the fight, Vegeta was able to fight on par with 1st Form Frieza, suggesting that his power level was around 530,000, nearly three times as high as Goku's power level of only 180,000 during the battle against Ginyu. When Vegeta strategically exploited the Saiyan Power boost, he expected it to give him enough power to defeat Frieza, but his predictions were wrong. Meanwhile, Goku went from a power level of 180,000 to a power level of 3,000,000 after only a single Saiyan Power boost, despite there being no apparent reason why his power should balloon to that level when Vegeta's didn't. This lack of consistency may explain why the Z-Fighters do not rely on the Saiyan Power boost after the Frieza saga.
Potential Limitations Edit
During the Frieza Saga, Vegeta tells Krillin that a Saiyan cannot increase their power if the wound is self inflicted, which is the main reason why Vegeta convinces Krillin to injure him so Dende could heal him, allowing him to grow stronger. However this limitation is disputed by Goku's increase in power after consuming Senzu Beans to heal from the injures he received during his extreme gravity training and by Cell powering up after his self-destruction. One possible explanation for Goku receiving a Zenkai during his training is that while some of his injures where self inflicted such as getting hit by his own energy wave, his power increased after healing due to the extreme nature of the training as the extreme gravity also took its toll on Goku's body thus Goku increase power after healing may have been the result of the damage done to his body by the extreme gravity and training itself as a whole, as a opposed to the damage he inflicted on himself by his own attacks (meaning it is possible that his self-inflicted injuries did not contribute at all to Goku's increase in power, and that it was the gravity and training to the brink of death that increased Goku's power after he healed). It should be noted that while Cell's self-destruction qualifies as a self-inflicted injury, it should be noted that Cell is an artificially created lifeform that is only partially Saiyan so he may not have the same limitations as pure Saiyans like Goku and Vegeta or even natural born partial Saiyan hybrids like Gohan.
- In the Box Sets of Dragon Ball Z, the term Zenkai is used at the ending of every episode.
- While the dub incorrectly implies that Zenkais only occur with Elite Saiyans, Goku a Low-Level Saiyan, receives them many times. This is confirmed by how Krillin states how Goku always grew ever stronger after recovering from fighting devastating battles.
- In chapter 303, Vegeta states that a Saiyan cannot experience Zenkai if the wound is self-inflicted. However, Goku, received a Zenkai after healing from injuring himself with a Bending Kamehameha and Cell likewise did after regenerating himself from self-destruction. However, Goku's Zenkai may have come from his extreme gravity training or the external nature of Goku's attack and Cell's Zenkai from his augmented/mixed Saiyan, Namekian, and possibly Frieza's race cells.
- It should be noted that Goku's Zenkai occurs before Vegeta reveals that it cannot be obtained by self-inflicted wounds, while Cell's occurs long after.
Pictures of Zenkai