Soul Masters' attributes fell into two categories.
One was the attribute of their martial soul. Once refined through the martial soul, a Soul Master's power manifested the corresponding attributes. This could be seen in the color of the Soul Power used when martial souls clashed; the Chen Clan's Soul Power was predominantly blue.
The other was the attribute of their Soul Rings. Converted through a Soul Ring, a Soul Master's Soul Power produced Soul Skills with that ring's corresponding attributes. The same principle applied to Soul Skills granted by Soul Bones.
For example, Chen Zixiu's Seven Kill Sword possessed three attributes: metal, water, and spirit. His Eighth Soul Skill, however, possessed earth, metal, and water. The earth attribute that allowed him to gather stones into a mountain came from his Soul Ring, just as the fire attribute behind the dissolving power of his Ninth Soul Skill-Accumulated Destruction Shatters the Bones-did. These all came from the innate abilities of the Soul Beasts within the Soul Rings.
Without using those Soul Ring skills, Chen Zixiu could not unleash earth, fire, or other such attributes, whether he simply swung his sword at someone, used inherited Soul Skills such as the ultimate moves of the Sword-Controlling Art, or even deployed his domain.
Thus, when adding Soul Rings, Soul Masters generally sought Soul Beasts with the same attributes or closely related ones. Those with a wind attribute, for instance, favored lightning- or fire-attribute beasts.
This both increased the power of their Soul Skills and reduced the losses during the conversion of Soul Ring attributes. This was the compatibility between martial souls and Soul Rings.
Therefore, when Soul Masters encountered a Soul Beast with exceptionally suitable compatibility, many would choose it even if its age was a little lower. For example, Ling Yunxiao had chosen that