We, the demon slayers are very strong! We shouldn't get sick!

That was what you thought before Tanjiro fell sick this week. You found yourself taking care of him, although he tries to convince you that he's fine and he should go and train. You refused, his body is too weak right now.

"I said I'm fine.. Come on..!" –He sounds defeated, like he's about to give in, and just lay there to take his medications. He gave you a light smile, before coughing...and coughing loudly.