Why did Tang San have two martial spirits in fantasy novel's Douluo Continent?

In the novel Douluo Continent, Hao Tianshui and Lan are two martial souls, which are rare twin martial soul teachers. There are only three known Twin Martial Soul Masters in Douro Mainland, and the other two are unknown Twin Martial Soul Masters. The current Pope of the Martial Soul Hall is Bibidon.

In the confusion of Tang San, he felt that no matter how fast he practiced, his blue and silver grass martial soul was still a waste martial soul, and it didn't have much effect. Lao Du Bo Gu told Tang San some secrets about the twin martial souls. Generally speaking, the inheritance of Wu soul is to choose a relatively strong mother to pass on to future generations. When the strength of the witch souls of both parents is almost the same, or even the same, one parent will be randomly selected for inheritance, or the witch souls will mutate. Elder Du explained that there are two prerequisites for the emergence of twin witch souls, as recorded in the secret book of Witch Soul Hall. First, parents' Wu Ling must be different. The farther the difference is, the greater the chance of twins' Wu Ling. Second, the closer the parents' martial spirits are, the higher the probability of having twin martial spirits.

Since the appearance of twin martial souls is closely related to the martial souls of both parents, let's talk about the martial souls of Tang San's parents. First of all, let's talk about Tang San's father, Tang Hao, who was born in Tiandaozong. He is a direct disciple of Tianli School and one of the best strong men. He is the youngest title of Douro in Douro mainland, and the scientific hammer, as the clan of the scientific Tianzong, inherits the martial soul, is the first and nemesis of all martial souls in Douro mainland, and is known as the strongest martial soul in Douro mainland. Let's look at Tang San's mother. Tang San's mother, A Yin, was cultivated by Lan Yin Emperor for 100,000 years. The existence of the spirit beast in 100,000 years is very strong, and the witch soul owned by the mother is not a simple blue silver grass but a blue silver emperor. The blue silvergrass in the Tang Dynasty has completely evolved into the queen of the blue silvergrass emperor. Taking the blue silvergrass as a gift field, the vitality and information of the blue silvergrass can be gathered and transformed into the vitality of the blue silvergrass, which can be described as "the wildfire is endless and the spring breeze is high".

It is precisely because the martial souls of Tang's three parents are very strong, and their qualities are almost the same. One is the most powerful martial soul in Douluo mainland, and the other is the blue and silver grass that is considered to be the abandoned martial soul. The difference between the two martial souls is huge, which makes Tang San inherit the martial souls of both parents and become a rare twin martial soul teacher.