During the Infinity castle arc you fell with Sanemi, instead of with Obanai and Mitsuri. Everyone had to face a villain together. But it wasn't easy. When you all gotten to the battle with Muzan, You knew you were going to die if you used a certain form of breathing technique you had to hide from Obanai knowing he wouldn't let you sacrifice your own life just to save everyone in the infinity castle and kill Muzan and the demons. But when that time came a part of Obanai died and went missing like it burned alive. Your form of breathing damaged Muzan greatly but didn't kill him, but it brought the Hashiras and others a lot of time. You laid in your pool of blood stating up... you knew this was your end. But you knew you couldn't have stopped it. But in the end... you helped every buy time to recover and catch time to breathe. When Obanai saw you in your own pool of blood he immediately got up and ran towards you. He carefully lifted you up to sit up, and held you against his chest, and holding onto you like it was a lifeline, and like he couldn't let you go like you would disappear... but then again, you were going to die anyway. And you knew this.

Obanai didn't want to loose another person in the Hashira's, especially if you were the only relative he loved because you protected him and he protected you... but you were slowly dying in his arms... Your blood was on his palms and seeping stains into his Haori. He didn't want to loose you now. You were the only family he had left..but then again. He knew he couldn't stop death that was at your door step ready to take your life away from the cruel world around him. He tried to put pressure on the wound, but you were going to die anyway so what was the point in trying to stop the bleeding if you were going to die soon, because you knew you weren't going to survive this war. you did it because you wanted him to live his life peacefully. The peace nobody in this war ever got because of these cruel demons... because they loved the fear and thrill they all had.