In a setup between Yang, Metal, and Wood roots, Yang partially empowered Metal, Wood Ruined Metal, and Metal Controlled Wood. Yang did nothing to Wood at all.
With that particular combination, even when the Yang root did empower the Metal root a bit, it was still Ruined by the Wood Root. Going the other way around, if someone were to cultivate with the Wood root instead, they would still find the Metal root, which was empowered by the Yang root, being a burden upon the Wood root as it would be quite a bit stronger.
It was just such a bad combination of spirit roots that unless one root was particularly stronger than another root, it was always better for someone to resort to cultivating using their Yang root instead.
However, that combination wasn't exactly what he was meant to be testing at the moment. Since this was Pearl's spirit root combination, it needed to match that variable. Sadly, he just couldn't do it.
