It took four tries for Azaroth to successfully concoct the Seven Star Yin Pill. The first few times, the reason for the loud explosion was because Azaroth didn't expect the reaction that occurred when his Azure Flames came in contact with the Moonlit Snow Lotus's Petals. Thus, he incorrectly manipulated the temperature and an explosion occurred.
However, after he corrected this mistake by significantly lowering the temperature of his Azure Flames, another issue occurred where the ingredients weren't fusing properly.
To correct both of these issues, Azaroth enveloped the Moonlit Snow Lotus's Petal in his Azure Flames. These Azure Flames were burning at a very low temperature and their only task was to stimulate the Yin Energy within the petals.
Azaroth also burned the other ingredients at the same time and when he felt that the timing was perfect, he fused the Moonlit Snow Lotus's Petal with the other ingredients.
