Bright Sacred Dragon Crystal?

"Today's different. The situation is not the same in the spirit soul battle. The strength of a spirit soul is closely related to the strength of the soul master. A Title Douluo's cultivation base is also vastly different from a Soul Douluo's. Usually, a soul master will obtain a final spirit soul upon attaining the Title Douluo's rank. It'll be his most powerful spirit soul. Although Tang Wulin is strong, his cultivation base is still not at the rank of a Title Douluo yet."

Dai Tianling said with puzzlement, "From what I know, many Title Douluos obtain an especially powerful spirit soul when they're at the seven-ring cultivation base. Later on, they'll keep adding soul rings until they reach nine rings!"