The relationship between Kaido and Yamato in the original work isn't clearly defined as a typical father-daughter relationship; in fact, it's just a little incompatible.
Yamato is Kaido's daughter, intended to be the future heir of the Beasts Pirates and the princess of Onigashima.
However, the problem lies in Kaido's distorted view of familial bonds. He doesn't need an heir, nor is he willing to pass on his dreams and ambitions to anyone else.
In Kaido's eyes, Yamato is merely a tool to aid him in ruling Wano Country in the future. To him, she is more of a subordinate with a special status than a daughter. As long as she is strong and obedient, that's all that matters.
Kaido doesn't show concern for her, and neither do the rest of the Beast Pirates.
Yamato grew up in such an environment.
To be honest, Ian found Kaido's way of raising Yamato to be quite troubling.
If he wanted her to be strong and obedient, shouldn't he have been stricter in disciplining her?
Kaido's hands-off approach from her childhood led to Yamato becoming independent, so expecting her to suddenly obey his commands is unrealistic.
Since Ian was brought under Kaido's wing, he has been trying to improve the father-daughter relationship between Kaido and Yamato.
After all, a fatherly Kaido is certainly easier to deal with than a ruthless one.
Ian's methods were straightforward. Since he and Yamato were the same age, they had been playing together since he arrived on Onigashima.
So, he frequently brought Yamato to spend time with Kaido, hoping to increase their father-daughter interactions.
Although Kaido is cruel and ruthless, he is still human, capable of feelings.
He shares a deep bond with Charlotte Linlin, and even cried after Big Mom's defeat.
In the end, while Kaido is harsh toward Yamato, she remains special to him.
If anyone else had been as rebellious as Yamato, they would have been crushed into a pulp long ago.
How else could she have reached the age of twenty-eight in good health and even mastered Conqueror's Haki?
Initially, when Ian started bringing Yamato to Kaido, Kaido was very impatient and even threw them both out on occasion.
Things took a turn when Ian pouted and told Yamato that he wanted to challenge Kaido-sensei because he aimed to surpass him.
Mr. Kaido, known for his love of fighting and his preference for strong opponents, saw potential in Ian and Yamato. They certainly had the talent and drive.
However, Ian had never explicitly claimed he would surpass Mr. Kaido. As a result, the lessons where Ian began calling Kaido-sensei his teacher started.
Over time, the relationship between Kaido and his daughter became more frequent and familial. Their bond deepened in this environment.
Eventually, when Yamato, who had been taught by Ian, began to show affection towards Mr. Kaido, he had grown accustomed to it and didn't mind.
Ian felt a sense of pride, though he was somewhat disheartened by the strength of the father-daughter duo.
"Mr. Kaido! Has everything been taken care of?"
A tall figure emerged from the room, dressed entirely in black leather: coat, pants, mask, and gloves, with only his eyes visible.
He was the formidable King the Wildfire, a prominent figure of the Beast Pirates.
Kaido casually set the two youngsters down and entered the room. "That Moria guy got away. Haha, he might come back for revenge eventually."
"If he dares to come back, I'll incinerate him without needing your help, Mr. Kaido," King declared with seriousness.
Ian smirked, appreciating King's loyalty to Mr. Kaido.
"No, King," Kaido replied, turning to Ian, who had been quietly following. "If Moria shows up again, let this kid handle it."
Ian pointed at himself, bewildered. "You want me to face Moria?"
"Leave it to us!" Yamato exclaimed confidently, puffing out his chest. "Ian and I are the strongest team!"
"Hmm. Did you hear what Yamato said?"
Mr. Kaido didn't hear it at all. He chuckled and headed up to the attic. "If you don't want to be killed by that guy, you'd better get stronger, kid."
Yamato grabbed Ian's hand and beamed, "Let's get stronger together!"
Ian managed a small smile.
He didn't really listen to anyone, least of all his father and sister.
Once Moria leaves Wano Country, he'll be just another fat, washed-up loser, soon to suffer a double decline in both strength and morale.
There's really nothing to worry about.
"Ian, don't let Mr. Kaido down," King said with a serious tone. "If you fail, I'll deal with you myself before Moria even shows up!"
But Uncle King, I'll forgive you this time.
"We won't let Dad down!" Yamato declared with determination.
King gave a soft snort and followed Mr. Kaido back to his room.
Yamato cheerfully tugged Ian's hand and dragged him downstairs. "Ian! Let's go have some fun!"
"Big Brother Ian! You're back?"
Just a few flights down, a boisterous voice called out.
Ian looked back to see a burly boy bounding towards them from around the corner, looking thrilled. "I heard you went on a mission with Boss Kaido!"
"Oh, it's Jack, right?"
Yamato greeted the newcomer with a smile and a wave.
The tall, oversized boy, who seemed to be about the same age as Ian but much taller, greeted Yamato warmly.
This boy, who is destined to become the future Jack of Drought, was a fishman taken in by Mr. Kaido last year. He's very talented and is being groomed as a future officer of the Beasts Pirates.
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