I have a feeling Ivy will be very vital in the future since she did research on Astral Chaos. In SCIV, she was trying to build a manufactured holy soul or something that would be capable of wielding SC until Cervy Beards showed up and ate half her soul so she had to use that artificial soul to save herself. Perhaps, Patty Cake will tell Ivy about the truth behind SC and the alchemist can try a different approach to create a holy being/item.
And yea, that whole Cass reincarnation thing didn't happen. Also, her sword cracked just as she walked near the Raphy's evil town so she didn't even go all out. Unless she's being abusing the holy sword to beat flour or something while on her journey. But she does have the power to dispel evil, according to Raphael. Who knows if being in Astral Chaos will taint her or something though.
Anyway, what one should worry about is how the number of malfested on the roster keeps increasing. At this rate, Edgemaster will either have to train all of them to 'master their emotions' like Maxi, or someone cough-Kilik/Talim-cough needs to do some serious purification.
And when I said holy warriors, i meant the peeps Hephasteus sent out. Which no one has seen yet. But they're currently getting eaten by

so who knows if we'll see any by SCVI.