When I was watching Bleach and first introduced to Kenpachi Zaraki, I felt there was something different about him. When he was looking for Ichigo to fight in the sneak entry arc, I was almost 90% sure that Ichigo was going to lose the fight against Zaraki. When the fight started, I was overwhelmed by his spiritual pressure, even though I was not in the anime. But when I saw the fight slowly turning against Zaraki, I was a little surprised. I was even more surprised when I saw him lose the fight. Even though he was not the main character, it was very depressing for me. After completing the arc, I thought Ichigo was able to win the fight because Zangetsu helped him, until the Hueco Mundo arc.
In Hueco Mundo arc when Zaraki arrived at Hueco Mundo with other captains and took over the fight against Nnoitra, I was sure that Kenpachi was going to win. But suddenly, it shocked me once again when Kenpachi was almost killed by Nnoitra. I thought that was it. Then suddenly, Kenpachi got a significant power boost and overpowered Nnoitra. Although he won the fight, there was a question in my head, and it reminded me of the fight between Zaraki and Ichigo. He almost got killed but suddenly got the power to defeat Nnoitra. Then again, I forgot it and thought that it was one of his insanities, until the Bleach Thousand-Year Blood War arc. In that arc, we get to know that Captain Unohana was the first Kenpachi. I was even more surprised that Unohana fought kid Zaraki and almost lost.
In the Thousand-Year Blood War arc, when Unohana was fighting with kid Zaraki, she said that she felt the joy of battle after many years. In that, kid Zaraki was so powerful that he was able to go head-to-head with even the first Kenpachi, Unohana. He almost defeated Unohana, but suddenly he lowered his sword and there was a significant decrease in his power. In the fight between Kenpachi Zaraki and Unohana in the Thousand-Year Blood War, we got to know the big secret that Kenpachi subconsciously lowers his power level to match his opponents, and when he is on the verge of death, he subconsciously boosts his power to win the fight. After years of fighting from his childhood, he lowered his power so much that the whole Bleach series showed us the weakest version of Kenpachi. In the Blood War arc, Unohana fought her final battle with Zaraki to get him to his full potential and killed him over and over again until he reached his full potential. In the end, he was able to reach his full potential, but Unohana had to die to achieve this goal.
Now there is still a question of why Zaraki boosted his power when he was fighting against Ichigo.
In the anime, we didn’t get an answer. But in my opinion, when Zaraki was fighting Ichigo, he had no intention of killing him or defeating him. He was only trying to enjoy the fight, and Zaraki always admired Ichigo because he was a strong opponent. At the end of the fight, Zaraki could have easily won the fight but would have had to kill him, which he didn’t want. He lost the fight on purpose so that he could spar with Ichigo, as we saw in the anime when he asked Ichigo many times to fight with him. Now that he has reached his full power and achieved his shikai, and will achieve his bankai there will be some awesome fights to see in the anime.
