Well, I was an idiot. All damage and noise were caused by a broken rod tip guide. The guide is made of ceramic and can be broken by careless retrieving.
I remembered that I lent the road and reel to a friend who was a fishing beginner while we were fishing together last weekend. He might damaged the tip guide.
Broken tip at a different angle. See the sharp edge.
I checked rod maker, St. Croix's website and found that they sell tip replacement kit at $5. Probably, this mishap happens often. For now, I decide to use braid line for the rod. I hope to fix it soon.