Tanjiro's connection to Yoriichi is not through blood relation, but through their similar appearances, which is due to the divine nature of Sun Breathing. (Also Read: Did Demon Slayer hire a Bollywood director for Season 3? Fans speculate!)
It appears to be nothing more than a simple coincidence that the Kamado men have the same auburn hair as Yoriichi, and the Hanafuda Earrings they've passed down that Tanjiro now wears are the very pair once worn by Yoriichi himself.
But if we are talking about the human form, then it's a big fat NO, because Tanjiro has just mastered the Sun Breathing whereas Yoriichi is the inventor of it, also he's way more powerful and holds an unfathomable battle intellect, larger than any Demon Slayer in history, so in conclusion, no one is remotely close to ...
Why Does Tanjiro Look Like Yoriichi? Even though the two are unrelated, Tanjiro Kamado bears a striking resemblance to Yoriichi due to the divine nature of Sun-Breathing.
Tanjiro is the descendant of someone who knew Yoriichi personally and was a good friend of his as well. Sumiyoshi was rescued by Yoriichi when a demon threatened his life. Since then Yoriichi often met him and they became close acquaintances.
Tanjiro's ancestor was a good friend of Yoriichi and arguably was one of his only true friends. Therefore Yoriichi gave the earrings as a gift, and since then they have been passed down the generations until they reached Tanjiro.
Rimuru Tempest becomes a God towards the end of the series and can travel back in time and travel between worlds. His space-time abilities alone would be enough to beat Yoriichi.
Gyomei Himejima is the strongest Hashira in Demon Slayer. Even the Hashiras who are filled with pride, acknowledged his skill and strength. As a child he was able to save a child from a demon by physically beating it for hours. He, along with Sanemi Shinazugawa were able to beat the Upper Moon 1, Kokushibo.
In his own franchise, Tanjiro is outclassed by most of the nine Hashira as of the end of season 1, including Giyu Tomioka. It's easy to compare Tanjiro's strength to Giyu's — since they are both demon slayers — and they even use the same element: water.
Though Tanjiro succeeds in making use of Water Breathing throughout the early parts of his adventure, he eventually discovers that he's better suited for Sun Breathing instead. Sun Breathing was the first Breathing Style utilized by Yoriichi Tsugikuni.
Tanjiro wasn't born with this scar on his forehead. Rather, he acquired it when tackling his younger brother out of the way of a falling pot of boiling tea. At the beginning of Demon Slayer, the scar was a light-pink, circular mark.
In the short memory piece that Tanjiro received from his ancestor, Sumiyoshi, it is shown that their personalities are very alike. Sumiyoshi, like Tanjiro, is shown to be kind, generous, honest, and humble.
The reincarnation theory suggests that Tanjuro is a reincarnation of a former demon slayer -- specifically, Yoriichi Tsuginkui. Yoriichi was regarded as the strongest demon slayer and the inventor of sun breathing. Sun breathing is the first breathing technique that all subsequent forms are based on.
However, the scar changed its appearance during the Final Selection when the Hand Demon gave Tanjiro a major blow to the head. The blow not only increased the size of his scar but changed its colour as well. The scar changed even more when Tanjiro fought against Gyutaro and Daki during the Entertainment District arc.
It has been said that no one has been able to kill an Upper Moon in a hundred years, since Upper Moon Six Daki and Gyutaro were killed. ”The demons with Muzan's thick blood coursing through them are demons that have gained a massive amount of strength from Muzan himself.”
The Water Hashira, Giyu, survived the "Infinity Castle" arc after fighting beside Tanjiro against Akaza and Muzan. Though his sword was snapped by Akaza, and he lost an arm to Muzan, Giyu fought with Tanjiro and his fellow Hashira with everything he had.
Yoriichi lived till old age, likely due to him having been born with the mark and thereby avoiding the curse altogether. Gyomei on the other hand did not activate his Mark until he was already older than 25. It was speculated that when he awoke his Mark during battle that he would likely die within hours.
Yoriichi Tsugikuni, the first swordsmen to ever use Breathing Styles, once nearly killed Muzan with Sun-Breathing, and Muzan has been both physically and psychologically scarred ever since.
It is revealed that Muzan's true fear of dying and immense desire to live and survive was due to him being born "dead," where his heart would constantly stop in his mother's womb and was assumed stillborn until he fought to breathe before his cremation.
Ultimately, Yoriichi is the only being Muzan ever feared as he personally saw him as the true "monster" between the two of them and to the very end he remained baffled as to how a being like Yoriichi came to exist.
Akaza was also one of Muzan's favorite demons out of all his subordinates. The reason behind this is Akaza's extreme loyalty to his master. The Upper Rank Three demon was always sent away on special missions, something the Upper Rank 1 and 2 were often denied of.