The 'A Bad Friend' manhwa's main plot centers around the ups and downs of friendship. It follows the characters as they encounter various situations that reveal the true nature of their friendships and force them to make tough choices.
It could be a story about a person who has an unseen friend, like a guardian angel. Maybe this secret friend helps the protagonist in various ways, such as protecting them from danger or giving them good advice at crucial moments.
I believe my secret friend, my guardian angel, has been with me through many things. For example, I was once in a hurry to catch a bus for an important exam. I dropped all my papers. My secret friend was there in an instant. They helped me pick up the papers and made sure I got on the bus on time. Their help was always timely and made me feel safe.