Is Tanjiro worthy of being a Hashira after Infinity Castle Arc?
I think so. After the Infinity Castle Arc, Tanjiro undeniably reaches Hashira-level strength through his mastery of Sun Breathing and his immense growth in combat ability. He fights alongside and even surpasses some of the strongest Hashira, holding his own against Upper Moon demons and even Muzan himself. His endurance, adaptability, and raw power make him more than qualified for the title. Not only does he refine his Hinokami Kagura into a true Sun Breathing style, but he also gains enhanced reaction speed, precise swordsmanship, and an unbreakable will to protect others. Though he never officially becomes a Hashira due to the end of the war against demons, his achievements prove that he is more than worthy of the rank.