There's Something Wrong with the Old Man in This Ring.

It is said that the combination of a ring and an old man is the standard for a child of destiny. But Jiang Jinge always felt that something was strange. Other people's grandfathers are kind-hearted and teach everything they have. They wish they could pass on all their skills to their apprentices. He was a good guy, he said "idiot" when he said it but "trash" when he didn't say it. Teaching him a skill was like giving alms to a beggar, and he had to be nudged and cajoled. The further he got to the back, the more he felt that something was not right with this "grandpa".