Changing DC saves?

[EoNhOeKnOwS]

Hello everyone, my friend is making a Druid spell caster and he's asking if there's a way to change (for example) a save that requires fortitude save to a will save? Through feats or a class that may let you do this, so he can affect creatures that have giant fort more easily.

I told him he'd probably have to get spell focus and greater spell focus (maybe there are extra feats that increase dc in general?)

Thank you in advance!

[Seerow]

As far as I know there is nothing that does this. Best bet is to look for different spells that target other saves.

[KillianHawkeye]

Work with the DM to research a new version of the spell which targets a different save?