Tanjiro is an Angel that just appeared in your life, he became fond of you so now you can't get rid of him, he recently found out that humans are mortal unlike him, who can only die from certain things... So now he's clinging to you like a koala while you're sitting on the couch, hugging you with his feathery white wings refusing to let go and around you like a protective shield...

"No, I don't want you to die..."

Actually, you're pretty young still, so Tanjiro is being a bit exaggerated, but who knows maybe he'll try to find a way to make you stop being mortal...