As Tokito pulls the spikes out of him after escaping the Water Prison Pot Blood Demon art, some lesser demons begin to gang up on him. We get some backstory on him, about how his mother and father were both kindhearted people. His mother, however, became deathly ill, and while going to get herbs for her, his father fell off a cliff and died in a storm.
With no mother or father left at a young age, Tokito spent his days with his brother, Yuichiro, who was harsh to him and said helping others isn't a good thing. He even pushed away the notion of them becoming swordsmen.
One fateful night, a demon invaded their shack, and Yuichiro saved Muichiro from a deadly attack, leaving him without his arm. In a fit of rage, Muichiro killed the demon by leaving it paralyzed outside until the sun came up. As Yuichiro was dying, he prayed that only he would suffer, and Muichiro would be okay.
Remembering all of this, and his brother's final words about him being kindhearted and helping others, Tokito unlocked new strength and became even faster than before, gaining marks on his face like Tanjiro has. Tokito made quick work of the lesser demons and then slashed Gyokko, protecting Haganezuka and the other swordsmith. After dealing a couple more wounds to the Upper Rank demon, now, the real fight begins...