I might also be interested if there's room (and good point Kate).
A char concept the plot planted in my mind, was a virginal priestess or archer (think the cult of Artemis) or monk or paladiness (a la cult of Athena), possibly of the same goddess, Serene, who's been tasked by other Serene clergy to investigate this transgression.
btw, I love the Divine Oracle PrC, and always thought it had a virginal-priestess feel to it, and likely would've thought of it for a priestess myself. But if Tagan or the DM don't want two of the same PrC as her char, that's absolutely fine and understandable. (In terms of realism, you perhaps would expect several of certain PrCs in a given region and none of others, rather than 1 of each, as they're often associated with certain organizations/churches/races/etc. ). Or if even two clerics is too redundant for you - would Serene have druids?
I love paladins, monks, and rangers too as I mentioned....if you have a sense of the current party class balance, I could try to round out that.
Maybe a divine-ish archer [Divine Archery feat?] (likely not Divine Oracle in that case, it has mage BAB iirc)....like Rosa from Final Fantasy IV.