Given Mizuki's mastery of the five elemental transformations, it was simply too easy for him to boost the power of Kakuzu's ninjutsu, especially in the area of Fire Style, which he excelled at most.
If he had not wanted to avoid arousing the suspicions of the Akatsuki members too easily, Mizuki had even considered having Kakuzu use even more terrifying ninjutsu.
Mizuki's skill with the five elemental transformations was on an entirely different level from Kakuzu's.
Knowledgeable but lacking mastery—that was the truest description of Kakuzu. Fortunately, his immortal body made him difficult to gauge, and five lives were enough to wear down many powerful opponents who did not know the truth.
Within Akatsuki, Kakuzu and Hidan relied the most on keeping their secrets hidden. Once their traits were exposed, they would be targeted the hardest.
Now that the new Kakuzu born from Mizuki's will had adapted to his body, he could also control the secret technique, Earth Grudge Fear, with ease.
Under Mizuki's exquisite mastery of ninjutsu, the combined power of the five elemental heart monsters was already far beyond what the original half-baked Kakuzu could compare to.
"Since we came looking for trouble with the Land of Fire's daimyo, naturally we were prepared to encounter powerful enemies. The Fifth Mizukage, Mei Terumi, and Sasuke Uchiha may be a little troublesome, but I am no weakling either."
"Is that so? Looks like you've improved quite a bit recently. Good. Still, I hope you're not just putting on a brave face and talking big. If you run into trouble, I may not come save you."
Kakuzu himself was already powerful. Even disregarding Earth Grudge Fear's five lives, his immortal body, which had no inherent weakness, made him extremely difficult to kill. Ordinary ninja, meanwhile, had limited stamina and chakra.
Perhaps