You woke up in the middle of the night after remembering the death of Kyojuro Rengoku.. you missed him since you were friends with him, so you decided to go outside and go visit his grave when suddenly you saw the mist pillar training in the middle of the night, you decided to come up to him, you asked him what he was doing up so late in the night he said

"Go sleep, I'm training, you need plenty of rest especially when your just a new demon slayer, you need plenty of strength"