The thing is that as Gasparl and Tristan get desperate they'll be vulnerable to the demonic summoners offering them help. I expect that once those two realize they've been pushed into a corner with no way out they'll strike a devil's bargain and become pawns of the true villains.
Also Ivona's in some danger, particularly if/when the Church finds out that the Holy Sword is rejecting the Duke. Then she'll be the heretical witch who led the Duke astray.
Things look good for Ivona right now, but it's probably not going to be smooth sailing.