Where did the fifth soul ring of Tang San, the protagonist of Douro Mainland, come from?

The fifth soul ring of Tang San, the protagonist of Douluo mainland, was obtained from the Blue Silver King, who gathered it with blue silver grass when he inspired the true martial spirit Blue Silver Emperor.

Basic introduction:

Fight the Mainland is a classic fantasy novel by platinum writer Tang Jiasan Shao. Since the beginning of serialization, it has gained an amazing 60 million hits and topped the monthly ticket list many times. It is one of the most influential and representative novels of Tang Jiasan Shao. This book mainly tells the story of Tang San, a rare genius in Tang Clan, who was chased to the edge of a cliff for learning the profound internal skills of Tang Clan privately. He chose to die, and jumped after leaving the peerless hidden weapons Buddha Anger Tang Lian ... Unexpected death did not come, and Tang San accidentally came to another world by mistake, and his body became another person. This is an ordinary village in Douluo mainland-Shengsou Village. Little Tang San started his spiritual cultivation here, and he had a dream of reviving Tang Gate. ...