Steam card titled' The Pair'
When I read 'pair', I thought it's implying they're two of the same thing as that's how you use the term 'pair'
A pair is a set of any two of the same thing.
Yoshiro and Soh are said to have descended together.
So indeed, they are a pair and ultimately the same. Yoshiro herself is implied a messenger of the deity as well in her lore. But dedicating herself to the Goddess then...doesn't quite make sense as she's already associated with the Goddess.
Unless her devotion led her to become divine and ascend into messenger and Soh is the result of that.